I suppose it depends what kind of coins your looking for.
Modern stuff i would imagine is a good place to find almost anything you want.
Worth looking for pre-decimal varieties perhaps that have not been attributed.
Overall if i just wanted a high end coin would prefer to leave ebay alone as alot is not very good although described that way.
Having just remembered you have just started collecting i suggest you leave well alone IMO, but feel you could get carried away with the thousands of coins listed
only to find in a few months some maybe for throwing away.
Pete.