Incredibly easy!
This is incredibly easy to buy and to add money to.  When you buy one you have to activate it before you can use it.  To activate it they send you an email with a link in it.  Once you click the link your gift card has the money in it.  If you just add money to an existing gift card, it goes on your card immediately. It's incredibly easy!  Also, the gift card can be used for anything at all on Amazon.