eBay tricks

Or just get a mate to bid.

Bad form, but I'm sure it happens.

Problem comes when your "reserve" bid wins the auction. Your item is unsold but eBay hit you with their fees because the item was officially sold.

At least that's what a friend told me.

your friend is very right. or at least thats what my friend told me to say.
my friend said that in this instance you could cancel the transaction with your bogus bidder after the auction thus avoiding any fees. however my friend tells me that doing this frequently on the same account with the same buyer and different items might make them look closely and then penisalise you. thats what my friend said.