Next you pay the phone off month to month, 2 year paying off the phone works a bit differently- Im sure somebody could explain it better. All i know is Next is more flexible when it comes to buying new phones every year
instead of $15/mo per line you get charged $40/mo per line when you are under contract.
So $25/mo per line more when you decide to go under contract.
AT&T Next you pay full-price for the phone divided by however many months you want to pay for it (20 or 24), but no increase on the monthly plan.
Yeah, subsidized phones on mobile share plans pay $40 per line instead of the $15 or $25 a month the unsubsidized (BYOD or Next) folks do.
The 15/25 difference is you pay $15/mo per line on a 10 gig or higher plan, and 25/mo per line on under 10 gigs.
That's why NEXT is cheaper than subsidized 2 year contract if you're on a 10 gig or higher plan.
if you're on a lower than 10 gig data plan then NEXT is more expensive, but only by about $50 over two years... and that $50 might be worth it since you get the option to pay it off in full any time and get it unlocked, which you can't do with the 2 year contract.
Thanks to everyone that answered!