You do know that if you do not specify shipping when you post the auction or bother to change the shipping terms to the auction it is counted as free shipping no matter what just thought I would let you know since your new.
when the auction is over the winner sends you the shipping address and they will send you the shipping amount like threw paypal etc you ship the item. since your new you will recieve your credits once they recieve the item. i would include tracking to protect yourself and the buyer. hope this helps.