Got your eye on some free-shipping merchandise at the Apple store but need to pay with Paypal? If you call the customer support number, they'll tell you that Apple won't accept Paypal. You can sigh and walk away, or you can point your browser to the PayPal Plug-in Page and set yourself up a Secure Card virtual credit card number, valid wherever Mastercard is accepted--including the Apple online store.
Tap on the phrase "Mac user?", tap, Continue, and then tap on Secure Cards. Use the Paypal tools to generate your (unique) MasterCard Secure Card number, which you can use at the Apple Store. You'll need the card number, the expiration date and the CVC2 number for checkout.