They sound like you bid a penny each time. But it costs you about 60¢ everytime you place a penny bid. You buy bids ahead of time -- people are surprised to find that their credit card is charged for those bids before they even use them.
And think: if a product sells for $20, that means there were 2000 bids on it. If each bid costs 60¢ then the seller is making $1200 minus the $20 it sells for.
And if it took you 50 bids to win that item for $20, it cost you $30 just to place bids. And consider how easy it would be to set up a bot (fake person) to bid against you and force you to keep buying bids.