You can actually shop anywhere,If you go to the withdraw funds section you will see an option called Shop online with a PayPal virtual card.
You just type the stores address you want in the browser bar they provide and you and it gives you a virtual master card number you use to check out with just like you are paying with a credit card.
Im not sure you can do this with all types of paypal accounts so you will have to check and see if that option is available to you in the withdraw funds section.It is also free,paypal doesnt give you a charge for doing it.