As anyone who has bought one can tell you, the cost of a smartphone is more than just the initial price of the device. You also have monthly payments to deal with, for voice minutes, text messages, and of course, data. You can choose to either be frugal if you can squeak on by with the bare minimum or you can go for the pricier package if you want unlimited everything.

In light of recent changes to smartphone data plans and in anticipation of potential new 4G plans, we've compiled and calculated the cheapest and most expensive pricing plans below to help you in your carrier decision. To keep things simple, we did not include corporate or family plans, and we also didn't include T-Mobile's no-contract price plan as the other carriers don't have a comparable model. All of the carriers have plans that range in between the cheapest and most expensive, but as these plans vary so widely from carrier to carrier, it was difficult to compare all of them. We decided that comparing just the cheapest and most expensive would be the most useful.

We calculated the cheapest plans by adding up the cheapest of all the voice, messaging, and data options (we assumed that most smartphone users will want at least a basic messaging plan rather than no messaging plan at all). Conversely, we calculated the most expensive plans by adding up the most expensive of all three options. As all four major carriers require a data plan with their smartphones, we've also included that by default. Typically, the costliest plans include unlimited voice, messaging, and data. For the non-unlimited data plans, we've also included overage fee information.

We also know a lot of smartphone users don't use a lot of talk minutes, but are ardent users of text and data, so we added up monthly plans with the lowest minutes but with unlimited text and/or data usage. Interestingly, only T-Mobile and Verizon have plans that don't require a voice plan at all. The Verizon one does let you make voice calls, but for 40 cents a minute, so it's for those who don't plan on making a lot of calls.

Last but not least, we added the cost of mobile hotspot/portable tethering to the chart for those who have a smartphone that can be used as a 3G or 4G wireless hotspot or modem.

*We've added $10 to the Sprint plans due to the carrier's recent decision to implement a premium $10 monthly data add-on for smartphones.

We understand all of the different pricing options can be confusing and we hope this chart is helpful to you. We admit that we were quite overwhelmed ourselves when researching this article--the carriers don't exactly make it easy. If you have anything to add, or if you have any questions, please reply in the comment thread below or send us an e-mail.