Can I "un-bid" something from Ebay?
I found this Wii headset and bid for it but then I found a cheaper one.
Unfortunately, once you put a bid in, it's binding. The only way you can get out of it, is if someone else bids higher than you.
No, but if you do win 90% of sellers will honor your mistake and will not make you pay.
You can always try writing the seller before the bid is over explaining that you want out of the bid. They may or may not have a heart and do as you ask.