Not much of an Atari guy myself, but I know this seller and was told of it’s rarity so I decided to post it. Big Five Software posted a little bit of history regarding this and Miner 2049er in this site. Digitpress gave Bounty Bob Strikes Back an R8. The last time this sold was probably closer to $400 (see rarityguide.com).
Listed at $499 with 3 offers already (he listed it last night).