These prices are based off how much these games have sold for on record. Eg from e bay, and auctions. https://www.pricecharting.com/ Price charting website is also a useful tool to use to check current values. I have heard of someone buying the Nintendo world championship for $10.00 at a game store without them knowing what the true value of it was lol.
RE: Top 5 most expensive video games in the world