After working in the cell business for a while, I can tell you how this is shaking out.
There are 2 ways to buy phones and services for most carriers.
1. Corporate Stores where all prices and strategies are set and cannot be changed per individual store.
2. Vendor Resellers where they buy devices (without much of a discount) from the carriers. They do not get much, if any discount. Since they own and bought them, they are now able to set prices to whatever they want. Even Free.
What they are banking on is the deal will attract new and renew customers to their store to start or upgrade their services with them. They get a part of every monthly bill for the duration of that contract.
Some limitations come from the Vendors.
1. They cannot upgrade you early or "cheat" in any way, the system is set up to not allow it.
2. They cannot always modify things on accounts that corporate stores can. Things like, if you upgrade with one of them and they put you on a new data plan and you are currently on and unlimited, they have limited option on what they can do, and so forth.
There are some trade-offs for going to a vendor or reseller, Some times you can get a great deal, other times, you end up not getting the best deal as you had hoped.
Just read the fine print.
