While BestCashCow.com strongly advocates people hold travel and rewards cards for the best value from their regular spend, The AT&T Access More Mastercard® from Citi has a great sign up bonus for anyone needing a new IPhone.
According to the terms of the card, when you spend $2,000 on the card within 3 months of account opening you can buy a new AT&T phone at full price with no annual contract and Citibank will credit the account for the cost of the phone up to $650 (exclusive of taxes, shipping, fees & wireless service). $650 will get you a 16 GB IPhone 6 with a 4.7 inch display (if you want increased storage or the the larger iPhone, your price will be higher so that you will have some out of pocket expense). There is an $95 annual fee which should also weigh in to your calculations.
Citibank will even let you buy the phone right away and as long as you maintain service with AT&T for 15 days it will count toward the required spend for your signup bonus.
Most people will generally find travel and rewards cards to be the most valuable cards for regular spend.
This card, however, is a great offer for a sign up bonus, especially since it will enable those who aren't up for a subsidized phone, those who don't otherwise qualify, and those who can find a better rate plan without a subsidy to get a new IPhone right away.