Where should I put tools for a shop/check if purchased?

I don't know if I'm overcomplicating this or not I have a shop that sells items, my first question is where do I keep the tools so they are in a good storage place and cannot be taken by exploiters? ReplicatedStorage, ServerStorage, I'm just wondering what's the best placement (the game is FE).

Second, how do I check if someone has already purchased an item? My original idea was to put a bool value inside each tool with false for not purchased and true for purchased, but if I have all the tools in the replicatedstorage for example and I just cloned them to player backpacks, wouldnt the purchased values be the same for everyone since it all just gets cloned from the same one tool? e.g If I bought a sword, I can't make the sword in the replicatedstorage say it's purchased because then everyone will have it as purchased