Straight Talk has been a major MVNO for many people because they offered unlimited plans for unlocked AT&T and T-Mobile phones for $45 per month. Well it looks like Straight Talk is no longer offering AT&T compatible SIMs, and will only offer T-Mobile SIMs moving forward. If you’re already an existing customer it appears you are okay because they will continue to provide service to existing customers. If you were thinking about joining Straight Talk, there is still one option left, but that window is closing fast as well. Wal-Mart might still have SIMs available in store or online. If you can get one, apparently Straight Talk will honor those SIMs that are still available for sale.