diff --git a/src/features/grid/components.rs b/src/features/grid/components.rs
index 571e63f..94f1e5a 100644
--- a/src/features/grid/components.rs
+++ b/src/features/grid/components.rs
@@ -74,4 +74,19 @@ impl Grid {
         *tile_state = mapper(&*tile_state);
         Ok(())
     }
-}
\ No newline at end of file
+
+    pub fn count_claimed_tiles(&self, tile_query: &Query<&TileState>) -> u32 {
+        self.tiles
+            .iter()
+            .flatten()
+            .filter(|&entity| {
+                if let Ok(state) = tile_query.get(*entity) {
+                    !matches!(state, TileState::Unclaimed)
+                } else {
+                    false
+                }
+            })
+            .count() as u32
+    }
+}
+
diff --git a/src/features/input/mod.rs b/src/features/input/mod.rs
index 3b7158b..0059c66 100644
--- a/src/features/input/mod.rs
+++ b/src/features/input/mod.rs
@@ -162,9 +162,17 @@ fn shop_keybind(
     mut commands: Commands,
     game_config: Res<GameConfig>,
     asset_server: Res<AssetServer>,
+    grid: Res<Grid>,
+    tile_query: Query<&TileState>,
 ) {
     if keys.just_pressed(KeyCode::KeyP) {
-        open_shop(&mut commands, &game_config, &asset_server);
+        open_shop(
+            &mut commands,
+            &game_config,
+            &asset_server,
+            &grid,
+            &tile_query,
+        );
     }
 }
 
diff --git a/src/features/shop/mod.rs b/src/features/shop/mod.rs
index ccb0cfa..b347b56 100644
--- a/src/features/shop/mod.rs
+++ b/src/features/shop/mod.rs
@@ -21,12 +21,14 @@ fn buttons(
     asset_server: Res<AssetServer>,
     mut inventory: ResMut<Inventory>,
     mut items: Query<&mut ItemStack>,
+    grid: Res<Grid>,
+    tile_query: Query<&TileState>,
 ) {
     for (interaction, button_type) in &mut interaction_query {
         match *interaction {
             Interaction::Pressed => match button_type {
                 ButtonType::ShopOpen => {
-                    open_shop(&mut commands, &game_config, &asset_server);
+                    open_shop(&mut commands, &game_config, &asset_server, &grid, &tile_query);
                 }
                 ButtonType::ShopBuyItem(offer) => {
                     if offer.buy(&mut inventory, &mut commands, &mut items) {
diff --git a/src/features/shop/ui/shop.rs b/src/features/shop/ui/shop.rs
index 0b260ab..4983b00 100644
--- a/src/features/shop/ui/shop.rs
+++ b/src/features/shop/ui/shop.rs
@@ -5,9 +5,11 @@ pub fn open_shop(
     commands: &mut Commands,
     game_config: &GameConfig,
     asset_server: &Res<AssetServer>,
+    grid: &Grid,
+    tile_query: &Query<&TileState>,
 ) {
-    // TODO: calculate tile_count
-    let offers = ShopOffer::list_all(game_config, 0);
+    let tile_count = grid.count_claimed_tiles(tile_query);
+    let offers = ShopOffer::list_all(game_config, tile_count);
 
     spawn_popup(
         commands,