You probably pay a pretty penny for your cellphone plan. And when you're spending dozens or hundreds of dollars a month, you want to make sure you're getting your money's worth.

If you look deep into the cellphone contract you signed or read your company's data plan extras, you'll start finding free stuff you might not be taking advantage of. Keep reading to find out some of the goodies I'm talking about.

1. AT&T

Every AT&T subscriber gets free stuff, but the juiciest freebies come with AT&T's Mobile Share Value Plan, a pretty broad mix-and-match plan that starts at around $40 a month for a bare-bones 3GB deal with one phone and goes up to $260 a month for a 10GB family package with four smartphones.

If you're a Mobile Share customer, you get free stuff like a monthly rollover deal, where the data you don't use rolls over for one more month. You also get free international texting.

But the biggest freebie is 50GB of storage on AT&T's cloud. What that means is simple: You can securely save loads and loads of photos, videos, music and files online.

There's more. There's an especially cool feature for AT&T cellphone customers who find it annoying to ask a barista for the coffee shop Wi-Fi password. At Starbucks and retailers like The Home Depot, AT&T customers just walk in and are automatically connected to the Wi-Fi. No password, no hassle.

Bonus: AT&T and DirecTV recently merged, and the new megacompany is offering a great deal to save you cash. For a limited time, $200 a month gets AT&T customers DirecTV and a 10GB data package with unlimited talk and text on four phones. Many customers will save $120 a year or more over separate phone and TV bills. Plus, for existing TV customers who switch to AT&T for cellular, the company is offering a $500 credit toward the purchase of new phones.

2. Sprint

Sprint offers freebies to subscribers to its All-In package, which starts at $80 a month and gives you unlimited data and one smartphone, like Apple's iPhone 6 (16GB). The big freebie is streaming TV using the Sprint TV app. You can stream TV networks like Fox News and TV shows such as "American Dad" and "Access Hollywood."

NASCAR Mobile, which gives you up-close NASCAR action, is also free with any Sprint data plan. It’s so up close, you'll hear and see drivers inside their cars during live radio coverage of races.

For sports fans, Sprint's unlimited data plans offer more free stuff. Namely, NBA Game Time packages that give you free radio coverage of every NBA game. It shows you stats from the game and you can watch highlights from the games while the players are still on the court.

Bonus: Sprint will pay off your current cellphone contract if you switch from it. Contact Sprint for specific details.

3. T-Mobile

If you do any traveling to Canada or Mexico or have friends and family there, T-Mobile has an enticing offer: Free calls, texts and 4G data throughout North America. And there's no roaming charge for data usage.

Though continent-wide plans are rare, T-Mobile offers it even with its cheapest ($50 a month, 1GB) plan. But it's not T-Mobile's only free stuff.

Other freebies include free in-flight texting on Gogo-enabled phones and a few non-Gogo phones. That way you can keep tabs on what's going on at home 35,000 feet below.

T-Mobile's Data Stash feature rolls over unused data to the next month. But it's available only on the 3GB and 5GB data plans, and it can't be used in Canada or Mexico.

Also, with any 4G LTE data plan, you get a free MLB At Bat subscription. That includes watching MLB.TV's game of the day and highlights from other games.

But free music may be T-Mobile's most enticing perk. Without eating any of your data plan, T-Mobile lets you stream as much free music as you want from Apple Music, iHeartRadio, Rhapsody and other music services. Plus, if you have T-Mobile's Unlimited LTE Plan, which starts at $80 a month for the first phone, T-Mobile throws in a great freebie: UnRadio, Rhapsody's commercial-free online radio app.

4. Verizon

Verizon offers more free stuff than NFL football games, but if you're an NFL fan, its free stuff starts and ends there. It includes live highlights from NFL games on Thursday nights, Saturday nights and Sunday nights, and it includes 24/7 access to watch NFL Network shows and games.

Beyond NFL, Verizon also includes the IndyCar app, which airs live radio broadcasts of IndyCar races. You can hear and see what's going on in the car and you can listen to the pit crews.

If you're traveling, Verizon offers free international texting, but voice calls and data are still extra. To really enjoy these perks, Verizon plans starting at $60 a month work best. But they come with lower-cost plans as well.

Bonus: Verizon recently ditched its two-year contracts. Find out how that move can save you money.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, free newsletters and more, visit her website at Komando.com. Kim also posts breaking tech news 24/7 at News.Komando.com.