(Andrew Harrer/Bloomberg)

Citigroup was fined more than $700 million on Tuesday, partly for misleading customers when it came to fees and using confusing language to make it more likely that customers would buy services they didn’t need.

The announcement is a fresh reminder that it can pay to check monthly statements and question unusual charges.

The average credit card charges six fees — although some charge as many as 12 — according to a survey of 100 cards by CreditCards.com. Many of those charges, such as late payment penalties, balance transfer fees and cash advance fees, are fairly common. But some credit card issuers charge fees for services that many people might expect to be free.

“The reality is that even though banks make billions of dollars off of these fees, most of them can be avoided,” says Matt Schulz, senior industry analyst for Creditcards.com.

Here is a look at some unusual fees that might come up — and what consumers can do to avoid them.

Fee for opening the account. The First Premier Bank Credit Card charges a one-time processing fee of $95 that customers pay when they open the account. The fee is not much more than what some people might pay in an annual fee, but only one of the 100 credit card companies studied charges it.

Cost of changing your mind. Cardholders who close their accounts and then change their mind may need to pay a fee. Several credit cards from American Express charge $25 for people who want to re-open their accounts.

Printing costs. Some credit card  issuers will charge between $1 and $5 for sending copies of monthly statements. In some cases, the fee only applies for people who want older statements.

Charge for a higher credit limit. The Credit One Visa Platinum card charges up to $49 for people who want a higher credit limit and the First Premier Bank Credit Card charges a fee of 25 percent of the approved credit limit increase. It seems counter intuitive at first — wouldn’t the company want you to ramp up your use of the card? But Schulz says issuers may be working with consumers who are rebuilding their credit, which might make them seem risky in the eyes of the card companies.

Fee for paying over the phone. Some credit card issuers charge $10 to $15 to people who want to pay over the phone through a customer service rep, instead of the automated phone service. Cardholders who pay online or set up automatic payments can typically avoid these added fees.

The money that card issuers get from fees is growing as consumers get better at paying their cards in full and avoiding interest charges. Total income from fees rose to $90.3 billion in 2014 from $79.9 billion according to data from R.K Hammer, a credit card consulting firm cited in the study. Credit card issuers may add more fees as they look for ways to increase revenue, the report notes.

But many consumers can avoid common fees by shopping around and choosing a card that matches their spending and payment habits, Schulz says. And some might get a break on fees if they just ask. For instance, about 90 percent of customers who asked for late-payment penalties to be forgiven had their requests granted, according to a separate survey by CreditCards.com.

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