When you purchase a buy it now item the purchase is "final and non-refundable"
uBid doesn't have a way to select auctions only.
All you have to do is set your maximum bid amount and as people outbid you, your bid price will automatically keep increasing.
Its very simple process, browse the auctions, register an account, place your bid.
Yes, they do accept debit and credit cards. Unfortunately, they don't accept PayPal.