To this days I have bought about 4 accounts from ebay.
Aprox $1,200 have been spent on accounts.
I cant lie, most of the accounts from ebay are amazing and pure greed and lazynes (I dont know how to write... sorry) obliged me to buy them.
at one point I bought a warrior containing full tier 3 (before TBC ofcourse) for about $500.
To this days, all the accounts have been banned.
My point?
Never buy an account from ebay, no matter how cheap or how good they look. Unless you live in the same region as the person who is selling (having a similar IP) your account will more than likely be banned in one point or the other.