If the MasterCard in your wallet carries a picture of your university's ivy covered walls, you are a member of an affinity program. If your political party, church, or trade association regularly sends you ads and promotions from internet service providers, home improvement or office supply stores, your organization is promoting its affinity program.

Affinity relationships have been around forever, you scratch my back and I'll scratch yours, being among the oldest of them, but they have become highly formalized in the last dozen or so years.

In the case of the credit card your alumni association or favorite charity convinced you to accept, the affinity relationship is a source of revenue for its sponsor. For every dollar you charge on your affinity card, the credit card company donates a small amount to its affinity partner. It is a very small amount, but with thousands of alum or members, it can add up to a substantial source of revenue - and a form of fund raising that is pretty painless for both the association and its "donors." So go ahead and splurge on that designer outfit, and get those Jimmy Choo shoes to match. It's a way of doing good while being very bad.

There are affinity programs out there, however, that can benefit you in more than just the feel good way. And some of the most rewarding affinity programs are available to buyers and sellers of real estate.

Before you even begin to search for a house or interview listing brokers, check to see if one or more of these real estate affinity programs is available to you. Employers, large organizations such as labor unions, educational institutions, big non-profits, even shopping clubs may offer an affinity program that can give you back a pretty substantial amount of money if you utilize their sponsored services when you buy, sell, sometimes even finance a home. While they are not technically affinity programs, there are several on-line referral services that offer non-cash incentives (large gift certificates, vacation packages, etc.), if you accept a referral to one of their recommended agents and close a deal.

There are probably dozens of variations on affinity programs, but here is a general description of the way they work.

An employer, almost always one of substantial size, signs an affinity agreement with a real estate company. This will probably also be a large company, regional if not national in scope. The real estate company agrees to rebate to its affinity partner a portion of the commission it collects from any sale consummated with the partner's employees. The employer may keep a portion of this rebate to compensate for any costs they incur in administering the program, but most if not all is passed through to the employee as cash after the closing. Where the real estate company also runs a mortgage company, there may also be a rebate for arranging financing through that company.

The real estate company assigns the employee to an agent who is willing to give up a portion of his commission in return for the business (this is commonly 25 to 40 percent of the agent's share of the total commission after his usual "split" with the real estate company. Agents have different splits, commissions differ from state to state, office to office, and the real estate company almost certainly takes a chunk out of the rebate to cover its own administrative costs, so it is difficult to know how much cash the buyer or seller actually gets at the end of the day. Enough to paint the living room or buy a new couch? Who knows? None of my customers ever collected more than $1,500 (in one of the priciest areas in the country) but every bit helps after all of those closing and moving costs.

Because rules differ, you need to get the lowdown on any affinity program before beginning your house or agent search. Some programs insist that you be referred to an administrator who will, in turn, refer you to an agent willing to participate in the program. This takes away a certain amount of freedom of choice, but insures there will be no problems getting your money at closing. Other programs allow you to collect your rebate as long as you are dealing with an agent within the affiliated real estate company. But get the rules up front and make sure your agent understands, both to protect yourself and to prevent your agent from breaking down at the closing table when he sees 35 percent of his commission disappear before his very eyes.

If your employer does not participate in an affinity program, there is a good chance someone else within your sphere of influence does. It may even be worth the membership fee to join a shopping club or other organization with such a service. But check it out thoroughly - both with the sponsor and with the participating real estate company.

Affinity programs are not available in all states because in some they are illegal. Twelve states specifically prohibit rebates by brokers and agents to customers and another, Iowa, is considering such a prohibition.

This, however, may soon change. The U.S. Department of Justice (DOJ) has just filed a civil lawsuit against the Kentucky Real Estate Commission for "limiting competition among real estate brokers." DOJ charged that the Real Estate Commission's regulations restricted competition and caused consumers to pay higher prices for real estate services. The Kentucky Real Estate Commission has 20 days to file an answer to the suit.