If it makes it easier to think of it this way... the only reason to buy outright (or enter a new contract, but NOT NEXT) on AT&T is as follows:
1. You have unlimited data on any number of plans that you plan to keep
2. You have an older data plan that they are allowing you to keep (older pricing).
You can't take into account your out of contract cost when comparing if NEXT is a good decision because it never will be, since you are not taking into account the new phone(s) you want to by.
Next has effectively shifted the way you pay. It is now completely transparent what you are paying for service and what you are paying to own/lease (I say lease because technically you have a choice to dump the phone every two years 12-18 months without finishing paying it off in full, but only if you start paying towards a new one).
NEXT is really the best option for those who want a phone every year since AT&T no longer allows early upgrades on their contracted plans.
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We do. My mother works for Berkshire Hathaway, and while I'm not sure of the discount she has, it's pretty substantial being that our bill is well below $200/month. I've done every number crunch for the US wireless landscape and we elected to stay simply because of this discount. I wish they'd have bigger ones for all these corporations. Customers really deserve them.
AFAIK the largest discount is 30% and it only applies to the main line. We have a 26% discount on our line. It's easy to calculate savings on the 10GB family share plan because its just 26% of $100 = $26. They also do a breakdown now if you login online where it flat out tells you your savings).
Years ago it used to be an account-wide savings, but they have switched that, and this applies retroactively (so even if you have contracted plans, current or older, it's only the main line that sees the discount. It also applies to the texting package, however.
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This is incorrect. You do have an agreement with Next with respect to the device. If you want to leave Next, you still have to pay the remaining cost of your device, which for some people could be a lot more than their old "ETF" given device costs will probably start at $650. But of course you then own the device which you can sell, etc.
I believe ETF's started at around $380 and went down $5-10 per month. Considering you are also not putting $200 down (instead it's about $50 taxes, give or take), as you would with a contracted plan (unless you wait and find a sale/deal), I would say it's pretty darn close.