Curse Store System

MC: "Man, I want that new game but I need money to buy it and my allowance doesn't come next month!"
???: "You want money, I know a way to make some."
MC: "Oh, how so?"
???: "Want to be an entrepreneur? Then open your very own store!!"
MC: "That sounds nice but I need money to open and run a shop along with other things."
???: "No no, you misunderstood my intentions. I'm giving you my old store to run on your own!!"
MC: "What's the catch?"
???: "Haha, it seems you are smarter then I thought. You see the store itself is a little bit special and you have to sell special items."
MC: "Special how?"
???: "It's a curse store and the items, of course, are cursed!!"