there is a time limit, i think if there are less than 12 hours to go then you can't cancel the bid, but you can E-mail the seller and ask them to cancel the bid, saying that you made a mistake etc. if there are more than 12 hours to go, Ebay do not make it easy, you will probably have to click on the " wrong amount bid" option, then you are supposed to immediately put in another bid. i have cancelled bids twice in the last few weeks, and ebay send me nasty messages, but i just ignore them, they don't do anything, we are all prospective customers who will probably buy something via ebay sometime in the future.