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People look at Samsung Galaxy S6 phones during a prelaunch event in Singapore April 10, 2015. Reuters

So you want to buy the Samsung Galaxy S6 or Galaxy S6 Edge, and you're more than happy to sign a two-year wireless contract. Before you take the plunge, take a look at price comparisons between the three major carriers that offer two-year contracts: Verizon, AT&T and Sprint.

With a two-year contract, customers pay a subsidized fee for their new smartphone, and commit to 24 monthly payments for service. At the end of a two-year contract, customers have the option to purchase a new smartphone with a new two-year contract or they can continue using the same phone, which would then be out of contract.

So, who offers the best deal and what's the catch? Keep in mind that these prices do not include taxes and other fees carriers might charge.

Verizon 2-Year Contract, 1GB Data, Single Line

Due at purchase (smartphone cost): $249.99
$50 Mail-in Rebate: + $50 (device is $199.99 after rebate)
Activation fee: $40
Monthly service cost: $60
Total year cost: $960
Total two-year cost: $1,680

Verizon is notorious for having costly service on its network; however, by the numbers, Verizon actually has the cheapest two-year contract option. That is, of course, if a customer adheres to the strict 1GB data limit of Verizon’s most basic service offering. Verizon has costly overage fees for those who exceed their data limits and a steep price increase for adding data to a plan. Adding just 1GB of data to a plan increases its total one-year cost to $1,140 and the overall two-year cost to $2,040.

AT&T 2-Year Contract, 1GB Data, Single Line

Due at purchase (smartphone cost): $199.99
Activation fee: $40
Monthly service cost: $65
Total year cost: $1,020
Total two-year cost: $1,800

AT&T, like Verizon, is known for having costly service on its network. Its prices for a 1GB data plan are even costly like Verizon’s. However, its next-tier offering of 3GB of data is $1,200 for one year and $2,160 for two years. Additionally, AT&T has a data rollover plan that allows customers to save unused data for the following month.

Sprint 2-Year Contract, Unlimited Data, Single Line

Due at purchase (smartphone cost): $199.99
Activation fee: $36
Monthly service cost: $85
Total year cost: $1,256
Total two-year cost: $2,276

Sprint is an anomaly of sorts among the mobile networks, offering an unlimited data plan with its two-year contract. Because of this, the overall cost of its service is more than Verizon's or AT&T's. An unlimited data option is appealing, especially when considering that adding just 1GB to 2GB of data on a Verizon or AT&T plan brings a customer’s fees to roughly the same level as Sprint’s unlimited plan. However, Sprint’s service is traditionally less reliable than Verizon's or AT&T's.