If you want to sell it on e-Bay, of course list it as RARE! and VINTAGE German 35mm SLR! camera with ORIGINAL leather case! Buy-it Now for some outrageous price, like $395, and use the word RARE! at least five times in the listing.
Surely you have seen this tactic on eBay camera auctions, right? It is a low-value camera, really, so clean it up realllllllly thoroughly, with Q-tips, rubbing alcohol, soft cloths, the works. DO NOT put Armor-All or anything on the body or the leather, but clean off the dust, and shoot some decent photos of it. Maybe you will attract the attention of some far-too-wealthy camera nut with a credit card. Cleaning this camera up will not destroy its valuable patina; these cameras are not inherently valuable, but if you can emphasize its good qualities, its vintage appeal, its rareness, you might find a sucker.