As of June 2016 there are (again) changes to Swagbucks Visa gift cards
View this item in the Rewards Store --> http://www.swagbucks.com/p/category/-3?srt=5&src=visa
When you receive your gift card you will get a code for prepaidcodecenter.com
When you first visit that site, before you can enter your code, you must sign up and create an account.
You can stack your Visas, but they will charge you a fee. Please explore the site on your own for any other services they may pprovide and fees associated.