I would assume the battery is still working fine, actually. But, yeah, I've seen complete copies sell for under $20 recently, so a loose cart isn't worth much. Most loose SFC carts in general aren't very desirable since most importers want complete games, so in terms of eBay and other outlets for importers, it may actually be easier to find a complete copy of a game than a loose one. Also, SFC prices in general seem to be down compared to where they were at 5-10 years ago. In the past, a complete SD3 could pull in $50 easily.

Also, what's with all the Solatorobo going on in here? o_O I'm glad I'm not the only fan here on Digital Press.