shit I use their invoice system....I like it because when a buyer pays through paypal, they just click buy and dont have to enter shipping costs because I have entered it through the invoice already, it allows alot less buyer error that way....I typically send a text invoice of my own as well because some buyers dont look at that other invoice for some reason....and ebay requires you to, well at least they say that you have to contact the buyer, I wish I could cut that step out, it would save me fuckin shit loads of time