So, I created a shop procedure the other day. When I speak to the clerk, I get to choose from 3 items. Now, here is the problem: I want the player to be able to buy these items several times, not just once. How do I pull this off?

Actually, I solved it the other day. This is how I did it:

Rooms: shop and hidden, not connected

Characters: clerk in shop, when spoken to, run shop procedure

Shop procedure: choose among 3 items, among them a health potion, if enough currency, move potion from hidden to shop and give to player

Health potion: when used, increment numeric variable HP and move object back to room hidden

rinse and repeat...