Identity theft is a growing problem in the United States, and dozens of companies offering various forms of identity theft protection have sprung up to combat it. Unfortunately, these services often do little to actually protect people’s identities, according to a study released by the U.S. Government Accountability Office (GAO).

Both the GAO study and consumer protection organizations like The Identity Theft Council point out that consumers have more effective, low-cost methods to protect themselves from identity theft. Here are some of their tips:

Monitor your own credit. You can get a free credit report from each of the three credit reporting agencies once a year at www.annualcreditreport.com. You can stagger your request from each agency so that you can check your credit history for any suspicious new account openings every four months.

In addition, one of the most effective things only you can do yourself is to scan your monthly credit card and bank account statements. If you see any irregularities, contact the financial institution at once and let them know if you believe any charges are the result of identity theft.

Place a fraud alert. You can place a free fraud alert on your identity if you believe you’ve become vulnerable for any reason, either because you lost your wallet, had your home or car broken into, or had your information stolen online. All you have to do is call any of the three credit reporting agencies (Equifax 1-888-766-0008; Experian 1-888-397-3742; or TransUnion 1-800-680-7289) and they will notify the other two.

Placing a fraud alert lasts for 90 days. Any credit provider will have to take extra steps to verify the identity of any person who tries to use your credit and open new accounts. It can be renewed for free every 90 days.

Freeze your credit. If you aren’t going to be applying for new credit for a while, one of the most effective things you can do to combat identity theft is to put a temporary freeze on your credit. You’ll have to call each of the three credit reporting agencies and may be required to pay a small fee ($5 to $10 each) to freeze your account, after which no one will be able to access your credit to open new accounts. It won’t affect your credit rating or your ability to use your existing accounts.

Keep in mind that while this shuts down other people from accessing your credit, it also stops you from opening new accounts. It typically takes three days for the agencies to unfreeze your accounts, so keep that in mind if you want to apply for new credit, or need to allow a potential new employer to access your credit report as part of a background check.

Do your taxes early. One of the most common kinds of identity theft is when people use a stolen Social Security number and other personal information to file a fraudulent tax return in the hope of snatching a refund. Your best defense is to simply file your return as soon as possible. Once the IRS receives your return, it shuts the door on potential identity thieves.