I think doing the whole peer to peer thing is very cool. Just a couple words of caution about Paypal. If someone started doing this on a larger scale and Paypal found out Paypal would say that your a money transmitter or that your otherwise violating their terms of service and may close down your account.

Another thing to be wary of, if you don't know the person your dealing with Paypal on intangible goods can be very risky as all someone has to do is open a claim and they will automatically get their money back because there's no tracking number.

Just wanted to point those two things out and encourage people to be cautious using Paypal but assuming your not going to go balls to the wall and assuming you know who your dealing with very cool