Consumers understandably get angry when they find their credit cards have been charged for something they didn't expect.

Sometimes it happens on a "negative option" sale they aren't even aware of. Sometimes it's a case of a merchant, who has their credit card information, placing multiple charges on their accounts and hoping they won't notice, or saying the consumer misunderstood the actual cost.

The online sales of "Your Baby Can Read" have drawn a number of complaints from consumers who say they agreed to one charge but were eventually charged much more. 

"I was told I would have a $14.95 trial fee," Anna, of San Francisco, told ConsumerAffairs.com. "Then my card would be processed another $66.00 if I chose to sign one."

Surprise!

Anna said she paid all the agreed-upon fees, then saw that her card had been charged another $66.

"I called and they told me the invoice states they are going to charge me a total of $214," Anna said. "The person I spoke with on the phone told me I would be charged 134.80 plus the tax. These people are very sleight of hand."

Another consumer, Heather, of Henderson, Ky., had read all the reviews and complaints about online purchases, so went to her local Wal-Mart. She says she's found a way to virtually eliminate the risk of having unexpected charges placed on her credit card.

Cash is king

"I bought the first stage at Wal-Mart for $25 and there wasn't any trial period or fee and I paid with cash. They have no clue about any of my credit cards," Heather told ConsumerAffairs.com. "Wow, a new discovery, going to a store to buy something instead of ordering it on the Internet!! Get some sunlight people and get out of your houses!"

In all fairness, it's possible to be subjected to unauthorized charges in an in-person transaction too, but Heather has a point. They can't keep charging you if your initial transaction is paid in cash.

It's helpful to remember that once anyone has your credit card information, they can essentially place charges on it at will, and you will be required to dispute it. Reputable businesses don't engage in that kind of behavior, but no one can control the actions of their employees 100 percent of the time..