Jumping on AT&T's cheaper unlimited plan? Not so fast...

In the battle for the best unlimited data plan, carriers keep firing off new prices and offerings every other week. It can be hard to keep track of which has the better deal. But relax. We'll keep it simple for you. Here's the breakdown of the current unlimited plans for the major US carriers. On Verizon, $80 gets you one unlimited plan for one line. And you can get this on four lines for $180. T-Mobiles unlimited plan starts at $70 and four lines cost $160. Sprints unlimited starts at $50, and five lines, not four is only $90 in total. That's obviously the cheapest but this is only a promotional price. After March of 2018, the plan starts at $60, still very cheap. AT&T is a little more confusing than the others. It has two different types of unlimited plans. The Unlimited Plus plan is the most expensive of the bunch. It starts at around $90 for one line, and four lines will be $185. But to entice you to also subscribe to Intellivision service, this plan will knock 25 bucks off your DirectTV or U-Verse TV bill. AT&T also offers a second much cheaper plan called the Unlimited Choice. It starts at $60 for one line. And it's cheaper because you're getting less that every other plan out there. Your speed will not be the fastest 4G can offer. It's limited to just 3 MBPS max. You also will not be streaming video in high definition. Everything is 480p tops and you cannot use the phone as a mobile hotspot. Now all the other plans include 10 gigs of data to share as a hotspot and you get HD quality video. So you have to consider if missing those things is worth the savings when Sprint's gonna cost the same and doesn't have those limitations. Now when you're comparing prices remember there will be additional fees and taxes added to your bill, except for T-Mobile. They fold that into their advertised prices. But of course you also have to take network quality into consideration. Verizon and AT&T are the largest but depending on where you live it doesn't always mean they're the best. T-Mobile is ranking high in many reports these days, and keep in mind unlimited never really means unlimited. The fact is if you gobble up data all of these networks are gonna slow you down. For example on Verizon if you Use 22 gigabytes of data you're speed is going to take a hit and other customers will be given preference over you if the network is congested. Throttling limits are about the same for every carrier, but T-Mobile offers the most leeway and waits until you hit 28 gigs before it slows you down. As competition heats up let's hope the deals get even better. Networks are growing to handle more capacity and consumers are hungry for better unlimited deals. As our app and streaming habits demand more data. For CNET, I'm Bridget Carey.