I know Dollar General is selling the Net 10 ones in my area for $50 bux and they are T-mobile based. I bought one and activated it and then called cs to have them ship me an At&t sim for it. My son was wanting his own phone anyway so I went out and started another BYOP line for myself and got a new number for myself and when the new sim came in I stuck it in the Inspira and let him have that as his phone. I was using At&t branded phones for my line but I ended up going just today and got me another Inspira for myself. I had a NOkia Lumia 520 (Nice Phone just couldn't dig Windows lack of apps) and then got an At&t Avail 2 (Underpowered piece of junk). Our Wallyworld here has Inspiras for Straight Talk but they are locked up so I couldn't see what network they run off of. On the front it just says GSM. The Inspiras at Dollar General actually said GSM-T.