USA Today article

Gray charges — those sneaky, unwanted, and unexpected charges that show up on your credit card — represent big business and an even bigger headache for unsuspecting consumers who don't always spot them.

It's estimated that one in three Americans are hit with credit card charges for things they never wanted or meant to sign up for — and while it might just be ten dollars here and there, it adds up to an average of $215 a year.

Here's what you can do to avoid these gray charges:

1. Curb your app attacks. There's a new gray charge culprit in town — supposedly free downloadable apps. They may be "free" when you press the "get it now" button, but sometimes there's a catch, such as fine print that says that by downloading the "free" app, you agree to a free-turned-paid subscription to a magazine, game or newsletter. Read the fine print.

2. Stay out front. It's also smart to make a note to yourself to cancel any trial of a service before your account is converted to a paid one. The more information you provide upfront, including a debit or credit card information, the more likely it is that whatever you've opted into won't be free at a later date unless you remember to cancel it. Put it on your calendar.

3. Scrutinize your billing statement. Be sure to read your billing statement every month and in detail, so you can catch any add-on charges. Research has shown most consumers rarely inspect their bills. According to BillGuard, only one in 10 perform a line-by-line audit.

4. Watch out for cost creep. Cost creep is a gradual price increase on your bill each month, often under the consumer's radar. The best way to avoid cost creep is to carefully inspect your credit card statements and compare them with the previous month's bill to look for any increases in recurring charges.

5. Look out for zombie charges.According to Daily Finance, zombie charges are charges that are deducted from your account after you've cancelled the service, while the company "processes the request."

6. Dispute dubious charges. If you do find a gray charge on your credit card statement, contact your credit card issuer and dispute the charge. By law, the credit card company has to respond to you.