You could only get items from the cashier in the pokemart. You can't buy the items in the aisles. The items on the aisles are probably useless but the cashier also sells useless items.
Pokemart Logic
You could only get items from the cashier in the pokemart. You can't buy the items in the aisles. The items on the aisles are probably useless but the cashier also sells useless items.
