Trade in your phone and get the Samsung Galaxy S6 and Galaxy Tab A for free from T-Mobile
The conditions of the deal/s may have changed since the initial publishing of this post.
If you're willing to get on T-Mobile's Jump! On Demand program and have a 2014 or 2015 flagship smartphone to trade in, the carrier is offering the 32GB Samsung Galaxy S6 for free ($0 down and 18 monthly payments of $0). One caveat is that you'll be basically leasing the phone from T-Mobile, and you'll have to return it after 18 months or pay for the device to keep it.
If you're rocking an older flagship, the carrier still leaves trade-ins on the table, but wants you to hand over $15 per month for 18 months to get the Galaxy S6. These phones are the Samsung Galaxy S4, the HTC One M8 and One M9, the Apple iPhone 5s, iPhone 5c, the LG G3, or the LG G4.
Usually, the Galaxy S6 can be leased from T-Mobile's via the Jump! on Demand program for $24 per month. This means that the trade-in value of these second-tier phones is only $162.
Those who lease the Samsung Galaxy S6 through T-Mobile's promotion and are willing to attach an additional data plan to their account can also get the 8-inch Samsung Galaxy Tab A, a mid-range Android tablet, for free ($0 down and 18 monthly payments of $0).
source: T-Mobile via Phonedog
Things that are NOT allowed: