Microsoft 640 Prepaid Cell Phone for AT&T Prepaid: Stay connected and productive wherever you are with this Prepaid cell phone, which features 4G LTE speed and Wi-Fi for flexible Internet connection options. Easily browse Web sites and flip through features using the 5" touch screen, and snap photos with the 8.0MP rear-facing camera.
I got this particular phone after losing two Android phones to the Stagefright trojan exploit. It was necessary to get a phone I knew would work and so far was unaffected by any hacks, exploits, viruses, or other afflictions. After checking several reviews, I settled on the Lumia 640. The phone is well-built, but the app store is barren, and the browser feels antiquated (No Firefox or Chrome, you're stuck with Internet Explorer, and the third party browsers aren't much better). Overall, it feels like a new phone from five years ago. But if you're concerned about security, why not go with the platform almost no one uses? After owning one, it's easy to see why.