If you are buying off ebay consider the following:
1. Is it real?
2. Does the seller have any proof? IE Genuine photo and not a copied one!!!
3. Search other similar listings and make sure you are not getting ripped off.
4. Do not buy if you are not too sure.
5. Check it out with the seller before you buy.
6. How long has the seller been a ebay member.
Hope you found my guide helpful.
Goodluck and thanks