When you place a bid, you make a commitment to buy the item if you win. There isn't really a "get out of jail free" card.
Some people make the mistake of thinking that they can put a bid on a number of the same item and only buy the cheapest one at the end of all the auctions.
If you put a bid on 5 different Nokia 2600s, and you win all 5 auctions, you're buying 5 phones.
This is the biggest mistake many people make when learning to use ebay.
No "Get Out of Jail Free" Card on Ebay!!