When you bid on eBay, you're entering into a contract to buy the item if you win the auction. Following through on the purchase is your obligation under eBay's rules. To avoid damage to your eBay reputation, you can use the bid retraction procedure if the circumstances that allow it apply, or request that the seller cancel the order.

Withdrawing a Bid

If the auction is still running, eBay allows bid retraction under three circumstances. None of them is because you no longer want the item, unless the seller changed the listing. If you thought you were bidding on a genuine gizmo and the seller changed it to a reproduction gizmo, retract your bid using the form eBay provides. You may also retract for a typo in your bid, such as $500 instead of $50, or if the seller is unreachable. To retract a bid if none of these apply, contact the vendor and politely ask if you may withdraw. Many people selling on eBay are service-oriented and will be understanding when you're honest and polite.

Cancelling a Purchase

The advice in the eBay Help Center for backing out of buying what you won on eBay is to contact the seller. If the seller is willing to cancel the transaction, it won't count against you. If not, and you don't pay for an item you won on eBay, it's recorded against you in your reputation. Repeated offenses may result in losing your account. It's a good practice to leave positive feedback for a seller who's helpful when you make a mistake.