I absolutely recommend PINZOO.COM!
My $40 refill sells there for $39.75... And then?
No! Sales tax... And then?
No! Miscellaneous local fees... And then?
No! Traveling to retail store to wait in line...
The card is even added to my wireless account automatically so I don't have to call my provider and enter some 147 digit number...
One of the very, very few things that sounds to good to be true, but is not.
The one experience I had with customer service was very pleasant and my issue was resolved very quickly.