A:AnswerI think it depends on the carrier. Verizon works with a different service than t-mobile. If you tell the people at Best Buy what carrier you want to use it with, they will sell you the proper phone. Typically it's the carriers (and sometimes Best Buy) that have the deals though, so check before you buy.
A:AnswerYou can buy any product outright...it just depends if you have enough on your gift card and are willing to pay the difference if your card doesn't cover the entire cost.
A:AnswerThis phone can be used on Straight Talk. Straight Talk operates on AT&T and Verizon towers. Any AT&T or Verizon locked device will work on Straight Talk.