I just got off the phone with a very friendly and helpful TMo rep. Since I ordered on 8/8 (after the tab promo start) she could just add the tablet to my existing pre-order; no need to cancel/reorder.
Here's my understanding of the deal:
- I would pay the full price of the tablet today plus tax
- over the next 2 years they credit my bill for 1/24th of the cost - $13.34 for the tab A, $10 for the tab E
- At the end of two years they have paid me back the cost of the tablet minus tax
- I would have to add a new line which for me is $10/month.
- Since I have no need for mobile data on the tablet (tethering to my phone works fine), the net "cost" of the tablet to me is $10/month x 24 months = $240, which is about $80 less than the purchase price (of the tab E).
So in my opinion, this deal is only good if you need a tablet on mobile data. Otherwise you aren't saving much ($80). And I would argue that in 2 years the value of the tablet will be pretty low since there will be newer models available but I'd still be "paying" for the tablet by keeping the line active. If I were to cancel the line they stop crediting my bill so I end up buying it either way.
(edit: I suppose if you were buying the Tab A it does end up being effectively free. The $10/month over 2 years for the extra line exactly equals their full price. Although Amazon sells them for $190 so...)
The rep looked for loopholes to get around the added line thing but couldn't find one. If someone has written evidence that you could cancel the line early or switch to a cheaper option I'd love to see it. Otherwise I'll, sadly, have to pass.