This deal has ended.
VirginMobile.com offers Beyond Talk Plans for as little as $35/month. For unlimited data, web, messaging, and talk it is just $55/month, which is a 40% savings on an equivalent plan from T-Mobile. Even better there is no contract so you're not obligated for a 2 year period. Phones start at $79.99 with free shipping. Sales tax is charged in most states.