If you're looking to save money with your GSM iPhone, Straight Talk provides a pre-paid option without unlocking or jailbreaking. Straight Talk offers iPhone owners an unlimited data, voice and text plan for just $45 per month. This is less than half the price of standard plans from AT&T.
Straight Talk is a MVNO (Mobile Virtual Network Operator), which means the carrier operates using other networks including AT&T and T-Mobile. Once you get a micro-SIM card from Straight Talk for your AT&T iPhone, the device won't know the difference.
Apple made big news in the US by expanding the footprint of iPhone carriers to nine different options. Although it was never officially announced, Straight Talk means the total number of iPhone carriers is actually 10. It seems like forever ago, but the iPhone was originally exclusive to the AT&T network. One of the advantages of GSM (AT&T) over CDMA (Verizon) is the fact that data can be sent to the iPhone while on a voice call.
When it comes to Straight Talk with a GSM iPhone, speeds are comparable to directly using AT&T and the coverage nationwide should be the same. This means that if your GSM iPhone is out of contract, there's no reason to continue paying twice as much for monthly service. Straight Talk is a brand of TracFone’s MVNO service, providing service with absolutely no contract from month-to-month. One caveat, according to GigaOM tethering on the unlimited data plan is not allowed, and some users have been flagged for using excessive amounts of data.