If it's what you're looking for and it fits your budget, go for it.
Email the guy and find out if it works and is compatible with your SNES (PAL or NTSC).
Email the guy -- RIGHT NOW! Because it's likely that eBay will pull the listing and if you have his contact info you'll be in a better position to buy it when they do. He's obviously trying to hide what it is because he doesn't have a picture or a description of it but if eBay catches on they'll pull it.