Updated from Dec. 13 to include additional information regarding T-Mobile data plan.
NEW YORK (TheStreet) -- Finding the best monthly wireless service plan used to be easier. You went into a store, selected a phone, chose how many voice minutes you needed and got a contract price. You signed a piece of paper and were on your way.
Now getting a mobile phone is more complicated. You need to decide on a payment plan (all the carriers say theirs are better than their competitors') and how much wireless data you need each month (unlimited voice calls and messaging are generally standard now). And you need to figure out whether your family or group qualifies for a discount. You also need to know which carrier provides the best service in the places you need it. Low monthly charges won't matter without a signal.
Let's compare the four major U.S. cellular providers and find the best plans for your brand new Apple (AAPL) iPhone 6 or 6 Plus.