Like many Americans, Krieger has a credit card that pays him a reward, or rebate, based on how much he charges.
Krieger said he spent about $9,000 on his co-branded American Express-Costco card last year and got $89 cash back.
After several phone calls, Krieger said he learned that the rebate formula he thought was simple was anything but.
He had thought he would get a rebate amounting to 1.5% of his charges.
With cash rebate cards, consumers can get something for nothing --- but it's hard to spot the best deals unless you read the fine print.
Moreover, charging purchases to get cash back is only a good idea if you can afford to pay off your monthly credit-card balance in full.
If you carry a revolving balance, you'll almost certainly pay more in interest than you will get in cash rewards.
In the past, the "must have" reward was airline miles, he said.
But consumers now view those with suspicion as airlines place greater restrictions on the use of free miles and people fear that financially struggling airlines may not be around when they are ready to redeem their miles.
"There are a lot of people asking themselves whether they want to turn from their airline card to something new," Robertson said.
"Because market share in the credit card industry is dominated by a handful of huge companies, they all have the wherewithal to dangle a shiny card in front of you."
The rebates are paid once a year in certificates that can be redeemed at Costco stores for cash or merchandise.
BankOne offers a cash rebate card that pays the cardholder a penny for every dollar charged up to $60,000 per year.