diff --git a/src/main/java/com/alttd/fishingevent/config/Messages.java b/src/main/java/com/alttd/fishingevent/config/Messages.java
index d4b5679..1b70b8c 100644
--- a/src/main/java/com/alttd/fishingevent/config/Messages.java
+++ b/src/main/java/com/alttd/fishingevent/config/Messages.java
@@ -50,6 +50,7 @@ public class Messages extends AbstractConfig {
         public static String NO_FISHING_ROD = "<red>You need to have a fishing rod to use this NPC</red>";
         public static String UPGRADE_GUI_NAME = "<green>Upgrade GUI</green>";
         public static String PRIZES_GUI_NAME = "<green>Prizes GUI</green>";
+        public static String SELL_GUI_NAME = "<green>Sell GUI</green>";;
         public static String NOT_INITIALIZED = "<red>There was an error initializing this GUI, please contact staff</red>";
 
         @SuppressWarnings("unused")
@@ -57,6 +58,7 @@ public class Messages extends AbstractConfig {
             NO_FISHING_ROD = config.getString(prefix, "no-fishing-rod", NO_FISHING_ROD);
             UPGRADE_GUI_NAME = config.getString(prefix, "upgrade-gui-name", UPGRADE_GUI_NAME);
             PRIZES_GUI_NAME = config.getString(prefix, "prizes-gui-name", PRIZES_GUI_NAME);
+            SELL_GUI_NAME = config.getString(prefix, "sell-gui-name", SELL_GUI_NAME);
             NOT_INITIALIZED = config.getString(prefix, "not-initialized", NOT_INITIALIZED);
         }
     }
@@ -98,10 +100,12 @@ public class Messages extends AbstractConfig {
     public static class OTHER_ERRORS {
         private static final String prefix = "other-errors.";
         public static String UNABLE_TO_CREATE_FISH = "<red>Unable to create fish, please contact a staff member</red>";
+        public static String UNABLE_TO_SELL_ITEMS = "<red>Unable to sell items, please contact a staff member</red>";
 
         @SuppressWarnings("unused")
         private static void load() {
             UNABLE_TO_CREATE_FISH = config.getString(prefix, "unable-to-create-fish", UNABLE_TO_CREATE_FISH);
+            UNABLE_TO_SELL_ITEMS = config.getString(prefix, "unable-to-sell-items", UNABLE_TO_SELL_ITEMS);
         }
     }
 }
diff --git a/src/main/java/com/alttd/fishingevent/gui/GUI.java b/src/main/java/com/alttd/fishingevent/gui/GUI.java
index c5b7ca3..9c5c0c5 100644
--- a/src/main/java/com/alttd/fishingevent/gui/GUI.java
+++ b/src/main/java/com/alttd/fishingevent/gui/GUI.java
@@ -11,7 +11,7 @@ import java.util.HashMap;
 import java.util.UUID;
 
 public abstract class GUI {
-    HashMap<UUID, GUI> GUIByUUID = new HashMap<>();
+    static HashMap<UUID, GUI> GUIByUUID = new HashMap<>();
     protected final Inventory inventory;
     protected final HashMap<Integer, GUIAction> guiActions;
 
@@ -44,4 +44,8 @@ public abstract class GUI {
         GUIByUUID.put(player.getUniqueId(), this);
         return true;
     }
+
+    protected abstract void closed();
+
+    protected abstract boolean canMoveItems();
 }
diff --git a/src/main/java/com/alttd/fishingevent/gui/GUIListener.java b/src/main/java/com/alttd/fishingevent/gui/GUIListener.java
new file mode 100644
index 0000000..8f199e4
--- /dev/null
+++ b/src/main/java/com/alttd/fishingevent/gui/GUIListener.java
@@ -0,0 +1,65 @@
+package com.alttd.fishingevent.gui;
+
+import org.bukkit.Material;
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.InventoryClickEvent;
+import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.event.inventory.TradeSelectEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.MerchantInventory;
+
+public class GUIListener implements Listener {
+
+    /**
+     * Handles clicking inside a gui
+     * @param event gui click event
+     */
+    @EventHandler
+    public void onClick(InventoryClickEvent event){
+        if (!(event.getWhoClicked() instanceof Player player)) return;
+
+        GUI gui = GUI.GUIByUUID.get(player.getUniqueId());
+        if (gui == null)
+            return;
+        if (gui.getInventory() != null) {
+            if (!gui.getInventory().equals(event.getInventory()))
+                return;
+        }
+        else
+            return;
+
+        if (gui.canMoveItems())
+            return;
+
+        event.setCancelled(true);
+
+        Inventory clickedInventory = event.getClickedInventory();
+        if (clickedInventory == null || clickedInventory.getType().equals(InventoryType.PLAYER)) return;
+
+        GUIAction action = gui.getGuiAction(event.getSlot());
+
+        if (action != null) action.click(player);
+    }
+
+    @EventHandler
+    public void onClose(InventoryCloseEvent event) {
+        HumanEntity player = event.getPlayer();
+        GUI gui = GUI.GUIByUUID.get(player.getUniqueId());
+
+        gui.closed();
+
+        GUI.GUIByUUID.remove(event.getPlayer().getUniqueId());
+    }
+
+    @EventHandler
+    public void onQuit(PlayerQuitEvent event){
+        GUI.GUIByUUID.remove(event.getPlayer().getUniqueId());
+    }
+
+}
diff --git a/src/main/java/com/alttd/fishingevent/gui/windows/PrizesWindow.java b/src/main/java/com/alttd/fishingevent/gui/windows/PrizesWindow.java
index a0c8fe5..877031c 100644
--- a/src/main/java/com/alttd/fishingevent/gui/windows/PrizesWindow.java
+++ b/src/main/java/com/alttd/fishingevent/gui/windows/PrizesWindow.java
@@ -33,4 +33,14 @@ public class PrizesWindow extends GUI {
     public boolean canOpen() {
         return true;
     }
+
+    @Override
+    protected void closed() {
+
+    }
+
+    @Override
+    protected boolean canMoveItems() {
+        return false;
+    }
 }
diff --git a/src/main/java/com/alttd/fishingevent/gui/windows/SellWindow.java b/src/main/java/com/alttd/fishingevent/gui/windows/SellWindow.java
new file mode 100644
index 0000000..a1f6bab
--- /dev/null
+++ b/src/main/java/com/alttd/fishingevent/gui/windows/SellWindow.java
@@ -0,0 +1,96 @@
+package com.alttd.fishingevent.gui.windows;
+
+import com.alttd.fishingevent.FishingEvent;
+import com.alttd.fishingevent.config.Messages;
+import com.alttd.fishingevent.gui.GUI;
+import com.alttd.fishingevent.points.PointsManagement;
+import com.alttd.fishingevent.util.Logger;
+import net.kyori.adventure.text.minimessage.MiniMessage;
+import org.bukkit.NamespacedKey;
+import org.bukkit.entity.Player;
+import org.bukkit.event.inventory.InventoryType;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.meta.ItemMeta;
+import org.bukkit.persistence.PersistentDataType;
+
+import java.util.*;
+
+public class SellWindow extends GUI {
+
+    private final Logger logger;
+    private final FishingEvent fishingEvent;
+    private final Player player;
+
+    public SellWindow(FishingEvent fishingEvent, Player player, Logger logger) {
+        super(InventoryType.CHEST, MiniMessage.miniMessage().deserialize(Messages.GUI.SELL_GUI_NAME));
+        this.fishingEvent = fishingEvent;
+        this.logger = logger;
+        this.player = player;
+    }
+
+
+    @Override
+    public boolean canOpen() {
+        return true;
+    }
+
+    @Override
+    protected void closed() {
+        Optional<NamespacedKey> optionalNamespacedKey = getNamespacedKey();
+        if (optionalNamespacedKey.isEmpty()) {
+            player.getInventory().addItem(Arrays.stream(getInventory().getContents())
+                            .filter(Objects::nonNull)
+                            .toArray(ItemStack[]::new))
+                    .values()
+                    .forEach(item -> player.getWorld().dropItem(player.getLocation(), item));
+            player.sendMiniMessage(Messages.OTHER_ERRORS.UNABLE_TO_SELL_ITEMS, null);
+            return;
+        }
+
+        PointsManagement pointsManagement = PointsManagement.getInstance();
+        NamespacedKey namespacedKey = optionalNamespacedKey.get();
+        List<ItemStack> itemsToMoveBack = new ArrayList<>();
+
+        for (ItemStack content : getInventory().getContents()) {
+            if (content == null) {
+                continue;
+            }
+            int points = getPoints(content, namespacedKey);
+            if (points == -1) {
+                itemsToMoveBack.add(content);
+            } else {
+                pointsManagement.addPoints(player.getUniqueId(), points);
+            }
+        }
+        player.getInventory().addItem(itemsToMoveBack.toArray(ItemStack[]::new)).values()
+                .forEach(item -> player.getWorld().dropItem(player.getLocation(), item));
+    }
+
+    /**
+     * @param itemStack ItemStack to check
+     * @return -1 if it has no points, otherwise returns points
+     */
+    public int getPoints(ItemStack itemStack, NamespacedKey namespacedKey) {
+        ItemMeta itemMeta = itemStack.getItemMeta();
+        Integer integer = itemMeta.getPersistentDataContainer().get(namespacedKey, PersistentDataType.INTEGER);
+        return integer == null ? -1 : integer;
+    }
+
+    private Optional<NamespacedKey> getNamespacedKey() {
+        try {
+            NamespacedKey namespacedKey = NamespacedKey.fromString("points", fishingEvent);
+            if (namespacedKey != null)
+                return Optional.of(namespacedKey);
+        } catch (Exception e) {
+            logger.warning("Error while creating namespaced key for points");
+            return Optional.empty();
+        }
+        logger.warning("Error while creating namespaced key for points");
+        return Optional.empty();
+    }
+
+    @Override
+    protected boolean canMoveItems() {
+        return true;
+    }
+}
diff --git a/src/main/java/com/alttd/fishingevent/gui/windows/UpgradeWindow.java b/src/main/java/com/alttd/fishingevent/gui/windows/UpgradeWindow.java
index 3e5bdcf..e28fafa 100644
--- a/src/main/java/com/alttd/fishingevent/gui/windows/UpgradeWindow.java
+++ b/src/main/java/com/alttd/fishingevent/gui/windows/UpgradeWindow.java
@@ -167,4 +167,14 @@ public class UpgradeWindow extends GUI {
     public boolean canOpen() {
         return canOpen;
     }
+
+    @Override
+    protected void closed() {
+
+    }
+
+    @Override
+    protected boolean canMoveItems() {
+        return false;
+    }
 }
diff --git a/src/main/java/com/alttd/fishingevent/npc/types/SellNPC.java b/src/main/java/com/alttd/fishingevent/npc/types/SellNPC.java
index 1490b53..ccda976 100644
--- a/src/main/java/com/alttd/fishingevent/npc/types/SellNPC.java
+++ b/src/main/java/com/alttd/fishingevent/npc/types/SellNPC.java
@@ -1,4 +1,86 @@
 package com.alttd.fishingevent.npc.types;
 
-public class SellNPC {
+import com.alttd.fishingevent.FishingEvent;
+import com.alttd.fishingevent.config.Messages;
+import com.alttd.fishingevent.gui.windows.SellWindow;
+import com.alttd.fishingevent.gui.windows.UpgradeWindow;
+import com.alttd.fishingevent.npc.LibNPC;
+import com.alttd.fishingevent.npc.NPC;
+import com.alttd.fishingevent.objects.EnchantmentTrack;
+import com.alttd.fishingevent.util.Logger;
+import com.alttd.fishingevent.util.NPCCreateData;
+import net.kyori.adventure.text.minimessage.tag.resolver.Placeholder;
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+import org.bukkit.scheduler.BukkitRunnable;
+
+import java.util.List;
+
+public class SellNPC extends LibNPC implements NPC {
+
+    private final NPCCreateData npcCreateData;
+    private final Logger logger;
+    private boolean isSpawned = false;
+    private FishingEvent fishingEvent = null;
+
+    public SellNPC(Logger logger, NPCCreateData npcCreateData) {
+        this.npcCreateData = npcCreateData;
+        this.logger = logger;
+    }
+
+    @Override
+    public String getName() {
+        return npcCreateData.name();
+    }
+
+    @Override
+    public void spawnNPC(FishingEvent fishingEvent, Location location) {
+        defaultSpawnNPC(fishingEvent, location, npcCreateData, logger, this);
+        this.fishingEvent = fishingEvent;
+        isSpawned = true;
+    }
+
+    @Override
+    public void leftClick(Player player) {
+        player.sendMiniMessage(Messages.NPC.UPGRADE_NPC_LEFT_CLICK_MESSAGE, Placeholder.component("player", player.name()));
+    }
+
+    @Override
+    public void rightClick(Player player) {
+        if (fishingEvent == null) {
+            player.sendMiniMessage(Messages.GUI.NOT_INITIALIZED, null);
+            return;
+        }
+        SellWindow sellWindow = new SellWindow(fishingEvent, player, logger);
+        if (!sellWindow.canOpen()) {
+            player.sendMiniMessage(Messages.GUI.NO_FISHING_ROD, null);
+            return;
+        }
+        new BukkitRunnable() {
+            @Override
+            public void run() {
+                sellWindow.open(player);
+            }
+        }.runTaskAsynchronously(fishingEvent);
+    }
+
+    @Override
+    public boolean showToPlayer(Player player) {
+        return super.showToPlayer(player);
+    }
+
+    @Override
+    public boolean hideFromPlayer(Player player) {
+        return super.hideFromPlayer(player);
+    }
+
+    @Override
+    public boolean isSpawned(FishingEvent fishingEvent) {
+        return isSpawned;
+    }
+
+    @Override
+    public void updateSkin(Player player) {
+        super.updateSkin(player);
+    }
 }