Yeah this game is just not very realistic. You think you're honestly going to be running a game shop and an unusually large amount of people come into your shop with signed merchandise, and even rare one-of-a-kind items? Not gonna happen.
Plus some of the items *may* be worth what the game says, but that's only if you find a specific collector of it, which you're most likely *NOT* going to find in the general populace. You're not gonna have someone come into your shop and ask for some long-dead game system nobody cares about with games that aren't even that great, and give you top dollar for it. Probably nobody wants the thing anyway.
One of the items is a desoldered chip worth only $3. Are you serious? No shop keeper in their right mind would buy such garbage and it would never sell.
Also author thinking all these common games are worth like $5 to $10 more than they are. Super Mario Bros -- $10 -- really!? Really? Come on now. You sound like one of those annoying people who grossly overvalues everything. You can go just about anywhere that sells used NES cartridges and pick up a Super Mario Bros. for like $4, $5 tops. Maybe even $3.
The concept is okay but I'm just going to have to disagree with the prices on a lot of these things and the feasibility of selling merch that requires an extremely niche market to the general public for full price value (and not having it sit in your shop for literally 10 years before you sell the thing).
If anyone's actually looking to buy/sell games and related merchandise, do not rely on this game to give you "accurate" prices. It's bogus prices. Game author doesn't know what the actual IRL prices half of that stuff actually goes for and typically sells for. Hint -- it's a hell of a lot less than he thinks.