Millions of Americans look forward to tax season. They're getting refunds and desperately need that check from the Internal Revenue Service. In fact, many are so cash-strapped they don't even wait for Uncle Sam. They turn instead to refund anticipation loans.

You've seen the ads. Simply sign a form with your tax preparer when filing your taxes pay a fee of between $35 and $90 and walk out with up to $5,000 cash against your coming refund check.

What you may not notice is the exorbitant annual percentage rate on that loan. But consumer groups have. They say these short-term, high-interest loans prey on the very people who can least afford them.

Critics of refund loans, as the loans are commonly known, point to the disparity between the tax advances and other credit offerings aimed at wealthier customers.

Tax preparers, both independent operations and major chains, charge interest rates that can run on an annualized basis well into triple figures, all for the privilege of getting money a few days earlier. The IRS further mitigates the risk to lenders with its Debt Indicator service, alerting them to any claims (child support, unpaid federal student loan) against refund-loan applicants' refunds.

"It's an outrageous rate for a really short-term loan which, by the way, is a fairly low risk to the lender, and it's an even lower risk because the IRS helps them flag who is going to present a risk," says Chi Chi Wu, staff attorney for the National Consumer Law Center.

"Yes, it seems like a small amount of money and it would be if this was a one- or two-year loan, but it's not. It's a 10-day loan. That makes all the difference in the world."