Editor’s note: This is a transcript of the audio file.

Just when you thought it was safe to use your cellphone, there’s a new, looming cellphone danger out there. I’m Katie Doyle with the Bankrate.com Personal Finance Minute.

Cellphone cramming happens when you’re billed for third-party charges you didn’t authorize. Because these fees are usually small, they can be easily missed on bills. But they’re costing consumers as much as $2 billion per year, according to the U.S. Senate Committee on Commerce, Science and Transportation.

The ruse typically starts with a text message for unwanted offers such as stock tips or horoscopes. Next, the charge may be automatically added to your next wireless bill. Charges may be buried under several headings such as “service fee” or “voice mail.”

But you can protect yourself from cellphone cramming:

Block all third-party charges.

Check your bill monthly. Only 1 in 20 people being crammed noticed the ruse, according to the FCC.

Avoid signing up for contests and sweepstakes, but if you do, always read the fine print on the offer.

For more on this and other personal finance topics, visit Bankrate.com. I’m Katie Doyle.