The HTC Radar 4G was $50 and now it’s free, at least online. They note:
For a limited time, when you purchase a HTC Radar™ 4G on T-Mobile.com or through 1-877-387-4324, you may qualify for a $300 instant discount and a $99.99 Web-only discount.
To qualify for the instant and Web-only discounts, you must activate the product on a new line of service with an Even More™ rate plan on a two-year service agreement. Even More™ Family Plans may qualify for up to five instant discounts.
Web-only discount may not be available in retail stores.
If you go to a store I would definitely press them on this and ask them to match it. You can check it out here on their site.