I buy stuff on Ebay quite often and the only problems I've had involved Canadian sellers...bought a powder scale a month ago and haven't seen it yet. In over 170 purchases the only misrepresented items were sold by fellow Canadians. I buy rifle scopes, old bullet moulds, loading tools, scope mounts, and rings etc., never a problem. Last purchase was a Springfield Armory 3rd gen. mount for an M14 about 10 days ago from a seller in Louisiana, took 5 days to get here and is better than described.
Its faster and simpler to buy scope rings that way than try to deal with the local gun shop where you have two choices for rings....Weaver and Weaver.
Ebay seems to have a good selection of Talley and Warne rings on a regular basis, both of which I can't find locally.
However I would prefer to buy everything I need here if only that were possible.