I think I’ve got it now.
I also have a version that subtracts when an item is consumed or sold or discarded, though I haven’t made those particular functions yet. Booleans will be used for, like, item/treasure boxes so they can be opened only once; while integers are used to keep the quantity from going over the max count and from increasing if the currency is less than 0 or less than the price. I will post a new thread later on how to make a shop widget that will let players choose some number of a desired item and calculate the money and quantity accordingly.