iPhone 6S, 6S Plus Prices: How To Get The Best Apple Inc. Smartphone Deal On AT&T, T-Mobile, Verizon, Sprint

Anxious fans will soon have the chance to preorder Apple's latest smartphones: -- the iPhone 6S and the 6S Plus. For the most part, their prices are straightforward, $649 for a 16GB iPhone 6S, $100 more for the 6S Plus. But toss the four major U.S. carriers into the mix and customers have even more choices to make, in addition to deciding between the rose gold and space gray iPhone.

Don't forget Apple as well, which launched its own iPhone upgrade program on Wednesday. The point is there are a lot of decisions to make even before customers get to the preorder page on Saturday. So before you rush to purchase the iPhone 6S or 6S Plus, take a look below to get a better idea about where you can get the best deal on Apple's latest smartphones.

Update 10:40 a.m. Friday: The story has been updated to include newly announced carrier promotions and prices.

iPhone Upgrade Program

If you’re not tied down to a specific carrier, choosing Apple’s own upgrade program can be a good place to start. Under the iPhone Upgrade Program, customers can choose their own carrier and purchase an iPhone 6S starting at $32.41 a month or $36.58 a month for the 6S Plus. After 12 months, customers opt to upgrade to a new iPhone or pay off the phone after another 12 months of payments. While the monthly cost is slightly higher than some carrier plans, it also includes the AppleCare Plus protection plan, which covers up to two cases of accidental iPhone damage. The one catch is that the iPhone Upgrade Program is only available at Apple's physical U.S. retail stores.

T-Mobile

For a limited time, the magenta carrier is throwing in an extra incentive to get iPhone 6S shoppers on its network. Starting Saturday at 12 a.m. PDT, T-Mobile customers can preorder a new 16GB iPhone 6S at $20 a month for 18 months, or $24 a month for the iPhone 6S, through the carrier’s Jump On Demand program. At the end of the term, customers can either return the phone to T-Mobile or pay $164 to keep the iPhone 6S, for a total of $524, or $126 less than the full retail price.

Verizon Wireless

New Verizon customers can expect to pay full retail price for the iPhone 6S, spread out over a period of 24 months. However, existing two-year agreement customer can continue under the subsidized pricing contract with the iPhone 6S. As an extra incentive, Verizon is offering customers trade-in credit for their old iPhones -- $100 for an iPhone 4 or 4S, $200 for iPhone 5 or 5C, $300 for the iPhone 5S, $350 for the iPhone 6 and $400 for the iPhone 6 Plus.

AT&T

Customers on AT&T have a couple of options available at their fingertips. Those that still prefer a contract can opt for a standard two-year contract for an iPhone 6S at subsidized pricing, likely starting at $199 for a 16GB iPhone 6S. Or if you prefer an installment plan, the carrier also offers the Apple smartphone through AT&T Next, which allows customers to upgrade after 12, 18 or 24 payments, depending on the plan. For additional savings, DirecTV or AT&T U-Verse customers that switch to AT&T Wireless can receive up to $500 in credit for each phone line.

Sprint

Sprint also offers its own installment plan where customers can pay off the iPhone 6S over the course of 24 monthly installments. Customers willing to spend an extra $10 a month can upgrade on a yearly basis. Alternatively, Sprint’s “iPhone for Life” program allows customers to get an iPhone at less than the cost of purchasing outright. The catch is, Sprint still owns the device and leases it to customers for a period of 22 months. The plan starts at $22 a month for the iPhone 6, though Sprint is running a promotion until Prices for the iPhone 6S under the carrier's leasing plan haven't been announced.

With the iPhone 6S, Sprint is running a promotion until Dec. 31 that allows customers to lease an iPhone 6 for $15 a month or $19 a month for the iPhone 6S with a smartphone trade-in. Without a trade-in, the plans runs for $22 a month or $26 for the iPhone 6S Plus. Customers can also purchase the iPhone 6S through traditional two-year contracts and Sprint's installment plans.