The freshly unveiled iPhone 7 opened for pre-order overnight and is set to hit stores in many countries as soon as September 16.
If you're thinking of upgrading, you'll have to compete for the limited supply of iPhones that have already reportedly delayed orders for those with Apple's replacement plan. But you may be able to snag a sweet $0 deal on the standard $649 iPhone 7 as the four biggest U.S. carriers compete for the initial rush.
Verizon Wireless
Verizon is temporarily offering a free iPhone 7 when users trade in their old iPhone 6, 6 Plus, 6s and 6s Plus for up to $650 credit. An iPhone 5, 5c, 5s or SE is worth up to $400 toward the purchase of an iPhone 7 or iPhone 7 Plus.
The following Android phones are also eligible for an up to $300 trade-in credit, Verizon said: Samsung Galaxy S6, S6 edge, S6 edge+, Note 5, LG G4 or V10 and HTC One M9.
These Androids are eligible for an up to $200 trade-in value: Samsung Galaxy S5 or Note 4, LG G3, HTC One M8, Droid Maxx 2 and Droid Turbo 2.
You get up to $100 for these Androids: Samsung Galaxy S4, LG G2, HTC One M7, Apple iPhone 4 or 4s, Droid Maxx and Droid Turbo.
Keep in mind
You're credited back over two years for your trade-in, so you need to stay with Verizon for two years for the promotion to fully pay off. Your trade-in must work and be in good cosmetic condition to get the credit. You can use it for pre-orders or when the phone hits the store, until the promotion ends.
T-Mobile
Users can temporarily trade-up their paid-off iPhone 6, iPhone 6s or either Plus model for a free iPhone 7 or a $120 iPhone 7 Plus. If you order online, there's a special trade-in process you must complete to lock in the deal.
For a $250 iPhone 7 (or $370 iPhone 7 Plus), you can trade in: iPhone 5, iPhone 5c, iPhone 5s and iPhone SE.
More memory costs $100 per tier.
Keep in mind
Again, this is a deal paid out over 24 months: If you cancel your service, the monthly credits will end and the remaining balance on the phone becomes due. Your credit must qualify you for the equipment installment plan, and you can't combine the offer with other device plan offers.
AT&T
An iPhone 6 and 6s trade-in, or the Plus models, get you a free iPhone 7 at AT&T. You'll need to have well-qualified credit for the AT&T Next or AT&T Next Every Year plans, so you should make sure that works for you.
Keep in mind
Of course, trade-in phones should be in good working condition and you should own it outright — or you'll have to pay up the remaining balance on it. If you cancel your service later, you'll need to pay the balance on your iPhone.
Sprint
You can get a free iPhone 7 for trading in any of the following phones at Sprint, according to their website: iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, Samsung Galaxy S7, Samsung Galaxy S7 edge.
You can sign up for any Sprint rate plan to qualify.
There's free delivery on Sprint.com as long as it's not a backorder. You can also get the iPhone 7 Plus with an 18-month lease and a trade-in for $5.61 a month.
Keep in mind
Again, the credit is paid out over 24 months, at $27.09 a month. You must be "well-qualified" to activate a new line or eligible upgrade with Sprint. And if you ditch your Sprint plan, the full balance is due.
Before you switch
As CNBC reported when the iPhone 6s hit the shelves, it can be incredibly complicated to figure out whether you should switch carriers to get an iPhone, since plan pricing can often vary based on whether you lease the phone or buy it upfront, use an installment plan from your carrier or Apple, or enter into a contract. On top of that, you have to consider whether promotions will meet the needs of how much data you actually use and how your credit score affects your leasing plan.
Here are five questions you can ask to make sure you're getting the best deal.