you could try ships, birds, planes, amateur astronomy, it's really up to your imagination. Also, you could try looking through the wrong end at your feet and other things, people seem really far away using this trick :-)
You really should be looking at either 8x magnification (smaller, lighter) or a maximum of x10. Anything higher is unnecessary, will suffer in poor light and will probably be too bulky. You have to decide between a conventional shape or roof prism and also what your budget is! Best makes are Leica, Zeiss + Swarovski but you can easily spend �500+ on a new pair.
I would go to a specialist retailer first to decide what you're really after and get some expert advice. Then try to find it on eBay!
Personally, I wouldn't use E-Bay. Best to go into a shop, where the staff are experienced enough to supply you with what you are looking for. At least if you're not happy with them when you get them home, you can always return to the shop.