Starting today and lasting through May 8, T-Mobile customers can swap out their old phones (even if they're from a different carrier), and get a guaranteed trade-in value that ranges from $50 to $200.
If your used handset is valued more than the promotion (like the Samsung Galaxy Nexus, which chugged out a value of $200) you will receive the higher value. All the deal requires is that the phone you're trading away actually work.
To see how much your old phone is worth, check out T-Mobile's calculator here. Keep in mind that the generated value is how much you would have gotten before the promotion. An iPhone 3G, for example, would have been $60.
I entered in some devices' names just to see what the resale value was. Although I wasn't surprised that a used Nexus will still get you back a decent amount of dough, it's a little disheartening, but completely expected, to see that Cricket's ZTE Chorus will fetch you only 7 bucks on the market. That's barely enough to cover a Filet-O-Fish meal at McDonald's.