If it is something you plan to buy anyways, you can put a couple bids on the item, if you don't win, you have the option to buy at full price, minus the value you spent on bidding so far.
So if you plan to buy something they offer, at full price anyway, it can be worth giving it a shot. You could bid until you get spend the value of the item in bids, then just pay the small difference to purchase the item that you were willing to pay full price for. That said, their full price is most likely MSRP and you can find it at a cheaper price, which means it is most likely not a good deal.
It is a gamble if you plan to keep trying to win different auctions for the same item until you win, and the odds are that you will pay more, or end up not getting the item at all, but paying for the bids.