gamegal

Hi, I am looking for a couple of rare games for the gift. Are these rare because of the boxes? Are the cartridges different?

I want to purchase two games for a video game fan for a gift. They are on an auction site. - are they rare? (Or good?) One is Atari 2800 Vanguard but it says 2600 on the cartridge. The other one is Atari 2800 Realsports Volleyball - same thing for the cartridge. What is a fair price for these? Thank you.