There are 35 stores in the game. Buying an item from each store is required for district completion for All Mine . Any item will do, it counts if you refill your ammo at the Friendly Fires if you bought all the weapons already and you don't need to equip what you buy. The stores are automatically marked on the map and you can hover over them to find out if you still need to buy an item from there, plus you can see how many stores you need in each district. Don't forget the desert stores as you don't need them for All Mine .