You open a Paypal account with your bank info. Then when a person wins, they can send the money directly to your Paypal account, via your email address. That way there is no lag time in mailing out the money, cost of a money order, etc. Some sellers accept payment in Amazon gift codes also. I know you are new, so feel free to ask any questions, and welcome to Listia! :)
Also, just because I had to learn all of this at first, too...if you verify your phone number, address, or bank account (you will get more shields under your name when you do), people are more likely to bid on items when you are new, and will bid higher if you are verified. That info doesn't go out to anyone, it just shows you are legit. Still watching!