Some auctions have bidding increments to prevent people from outbidding each other by insignificant amounts like a penny. It makes it so that people have to be serious about placing a bid because they are offering a reasonably higher price than the person that bid before them. For example, if an item is currently listed for $1,600, a bidding increment might be set at $100, which means the next bidder must offer at least $1,700 in order to participate.