Credit-card scam artists are continually coming up with new scams, while improving upon old ones. A major scam that's in the news these days is a seemingly innocuous $9.84 charge appearing on many people's credit card statements.

It may seem harmless and minor, but that's the point. The scam is perpetrated by those who have stolen great gobs of credit card numbers, and they're charging a modest sum on each one. (At Target alone, for example, tens of millions of customer accounts recently had data stolen, and Target is one of many such huge corporate victims.) The scammers are correctly thinking that most people won't notice, or won't bother contesting, such a small charge. If you see a false $9.84 charge, though, don't ignore it.

What to do
First off, remember that it's not just a $9.84 charge you need to look out for -- scammers might charge any small or large amount to your account fraudulently. If you find any false charge, contact the issuing bank or card company immediately. Ask that the charge be removed and a new card issued.

This can serve as a handy reminder, too, that when it comes to security, you should favor credit cards over debit cards, because regulations protecting you against fraud are stronger for credit cards than debit cards. Also, if you often buy things online or over the phone, handing out your credit card number in the process, only do business with reputable outfits. The FBI offers even more tips on avoiding credit card fraud.

Be proactive, too, checking not only your credit card statements but also your credit reports regularly.

Other scams
This is just one of many scams perpetrated upon a trusting public. The folks at scambusters.org found "phishing" and identity theft to be the biggest scam categories in 2013, followed by lottery and sweepstakes scams, where gullible people cough up dollars to collect their even bigger alleged winnings. Third on their list were fake online shopping sites, eager to take your credit card numbers and not send you the items that you believed you were ordering.

Another growing scam category is tax-related fraud. For example, scammers who have your Social Security number and name might be able to snag your tax refund before you do. And with that information, they might even be able to apply for credit cards in your name, using their own addresses.

A bit of good news is that credit card companies hate these scams, too, and once they notice patterns such as widespread $9.84 charges, they often take steps to prevent damage to customers and their own accounts. But they'll never control it all, so we all need to be smart and wary when dealing with credit -- and debit -- cards.