I will be accepting paypal. I'll also take cash, money order, or a check if you're willing to wait for it to clear.
Seeing as how stickers are relatively cheap to get hold of, I can afford to front the money to get them made and shipped to me. As a result, I will not be taking payments until I have them in my hands.
This has the added advantage of making it easy for me to figure out the price - I don't have to worry about the cutter upping the price on me and putting me into the red after having confirmed a price here.