Most of the old EM games are somewhat rare, at least compared to the classic vids. The one you've pictured I'd pay $400 in working condition. Someone else might pay more, others wouldn't dish out more than $250.
There was an EM and rifle game website, but for some reason its not popping up on my computer. It listed damn near every EM and rifle game(and others) that was ever made; and had info on each one of them.
If you can get it cheap, and it works, hell go for it. If its not working, these can be a bear to get working if you don't have the knowledge. Quite different from video games.