$0 up front + $27/month (phone) + $0 activation (free on AT&T Next) + $65/month (service, 2GB data) * 18 months = $1656 total cost (without taxes)
$199 up front + $40 (one time activation fee, required) + $80/month (phone subsidy + identical 2GB plan) * 18 months = $1679 total cost (without taxes).
If you paid the $199 upfront, then after 18 months, your still on contract and can't upgrade for another four months and you paid $20 extra.
If you paid $0 down and $27 a month, you saved (an admittedly tiny amount) of money, and you can also upgrade six months earlier at no extra cost.
$0 up front + $27/month (phone) + $0 activation (free on AT&T Next) + $65/month (service, 2GB data) * 18 months = $1656 total cost (without taxes)
$199 up front + $40 (one time activation fee, required) + $80/month (phone subsidy + identical 2GB plan) * 18 months = $1679 total cost (without taxes).
If you paid the $199 upfront, then after 18 months, your still on contract and can't upgrade for another four months and you paid $20 extra.
If you paid $0 down and $27 a month, you saved (an admittedly tiny amount) of money, and you can also upgrade six months earlier at no extra cost.