Trade in value

Just looked at that sight. If you can sell them for those prices, go for it. Some of the game traders in my area sell for cheaper. There was a couple that were flip flopped (Mario 3 says $14, I think I've seen it for 20).
Contra is not $26. $15 maybe.
Mike Tyson punchout same.
Friday the 13th is about $7-8, not 13.

Just a few I saw.

 

And if you ever see Nintendo world championship, watch out for fakes. It is extremely rare and that 10k price tag is legit what people sell it for.