Q.Can credit card companies charge interest on balance transfer fees? There was nothing in the promotional materials that advertised the APR on transfer fees.

A.Yes. And that's not just the case with balance transfer fees. Virtually all fees are billed as a purchase, added to your balance and charged interest.

The fact that this wasn't disclosed in the promotional materials doesn't surprise us. But we guarantee you that it's buried somewhere in the small print of the voluminous contract you've received at one time or another.

By making their contracts as long and complicated as possible, the credit card companies have learned they can hide all sorts of bad things in them. Lenders have turned something that started out as no more than a couple of pages of consumer-friendly information into a devious obfuscation.

The Credit Card Accountability, Responsibility and Disclosure Act, which protects consumers from the industry's worst abuses, may help when it goes into effect in February.

But the willingness of lenders to manipulate and mislead consumers is one of the reasons President Obama is advocating a consumer financial protection agency. He argues that consumers can't avoid surprises such as this without some help.