PayPal is a great protection for the both the seller and buyer.
As a seller they don't have to be afraid that a check would bounce (I know you wouldn't both others might), they don't have to pay the fee to cash an international check, and they wouldn't have to pay the fee if the check did bounce.
As a buyer, you know that your personal information is protected (the seller just gets a message "Mrs Jones paid you $25", not details Mrs Jones used Visa account number 4...). Also, if the sale doesn't go as planned (such as the product not showing up) you get your money back.
You can read all about it at the PayPal site. It really is a win, win situation.