Atari 5200 find, can you spot the gem?

[Penguin]

So I was browsing craigslist the other day and spotted a lot of Atari 5200 games. So I decided to do some research, and found out that one of the rarest games for the system was in the lot. Ended up getting all 24 games for $20. Pretty good if I don't say so myself. I know Meteorites is the gem of the lot, any idea what its worth, also are any of the other games of notable value? Any help would be appreciated, thanks!

[Atarileaf]

atari2600.com is selling a loose copy for $80 said to be in "excellent condition". I'm not up on the 5200 perse but that's the only price I could find as a comparable at the moment.