Only in rare occurrences are you able to retract your bids. eBay only allows retractions if the following occurs:

1) You accidentally entered a wrong bid amount. For instance, you bid $99.50 instead of $9.95. Keep in mind though that you need to re-enter the correct bid amount right away. You can use "wrong bid amount" as an excuses to retract your bid then walk away from the auction.
2)The description of an item you have bid on has changed significantly. If the seller changes something then that's their fault and if you don't like what's been added or removed from the description then you have the right to cancell your bid.
3) You cannot reach the seller. This means that you have tried calling the seller and his or her phone number doesn't work, or you have tried emailing a message to the seller and it comes back undeliverable. This does not mean that you can retract your bid if the seller doesn't answer your questions because questions should be asked before bidding not after.
4) Someone has bid on an item using your User ID and password. If you were logged into eBay and someone using the same computer places a bid then you are not liable providing that you can provide eBay with proof .

Note:
-Keep in mind that your total number of bid retractions in the past six months will be displayed in your member profile.
-False bid retrations are thoroughly investigate by eBay. Abuse of this feature may result in the suspension of your account. Bids retracted within the last 24 hours of listing can be viewed as bid shielding, which is a serious violation of our policy.

You can't retract your bid if,
- You change your mind about an item.
- You decide you can't afford what you bid.
- You bid higher than you promised yourself you would
- You find a better deal elsewhere.
- You didn't get all your questions answered about an item.