Can't get a home equity loan?

Or a do a cash-out refinancing?

The Rex Agreement is the latest way to pull cash from your home.

But it's a costly alternative you should avoid.

While Rex Agreements provide cash in exchange for a piece of the profits when you sell your home, the ultimate cost could be more than you bargained for, according to Chicago Sun-Times columnist Terry Savage.

Here's how a Rex Agreement, or Real Estate Equity Exchange, works:

Your home is independently appraised. Homeowners must have at least 25% equity in their homes to qualify.

You sign over a portion of your future home equity growth to Rex & Co. for a cash advance. The amount is determined by how much money you want.

An example on its Web site says that a homeowner sharing 50% of the equity in a $750,000 home will receive $107,000. And remember, that's not a loan. There are no monthly payments involved.

Rex & Co. makes its money back when you sell. In that example it would get half of the gross equity (before real estate commissions and fees) plus whatever you were paid -- the $107,000 in the above example.

If the owners had 35% equity in the $750,000 home when they sold, Rex would get all but $24,250 of that $262,500. Closing costs and real estate agents would probably gobble up the rest.

"The simple fact is that you aren't getting enough out of this deal," Savage says, "even though that chunk of cash is enticing."