Never used it, and not exactly a scam, but users pay for each bid they make and then the winner pays for the item + delivery; auctions can also be extended by last minute bidding (and, I would guess, by imaginary bids until Telebid have made enough profit).
If an item gets enough bids (and I suspect it is rigged to guarantee that there are always enough bids) then Telebid will have made enough out of the bids to pay for the item two (or more) times over. I guess you could get lucky and make the winning bid first time, but don't count on it!