Update: Amazon just updated the deals and dropped many of the prices down for customers looking to upgrade. For example, the RAZR M is now also just a penny for those renewing.
If you're looking to abandon your existing carrier and move to Big Red, then the RAZR M is a great phone to choose for the transition. And now you can grab it from Amazon Wireless for only a penny (Black, White). That's a top-notch phone with Jelly Bean (4.1.x) for basically free - and it's still $99 at Verizon.