Scraping together the down payment for a house is one of the biggest challenges facing would-be home owners, especially first-time buyers. Some young buyers still turn to the Bank of First Resort -- Mom and Dad. But for many others, there is down payment help available from several non-profit agencies that enables thousands of people each year to buy homes they otherwise might not be able to purchase.

In fact, nearly one-fourth of the 623,000 people who bought FHA-insured homes last year got some extra aid from these "down payment assistance programs" or DAPs. That means some 13,200 FHA-backed homes sold each month last year involved DAPs, HUD data show. And so far this year, the monthly number is more than15,700, or 30 percent of all the FHA-backed homes sold in the first five months of the year.

HUD keeps track of where the help comes from because lenders want to know the origins of down payment funds. Lenders routinely check the bank accounts of people buying homes and will question the source of any large, unexplained deposits. If the home buyer says the money is a gift, the lender will ask for a formal "gift" letter from the source to ensure it is a gift and not a loan. If it is a loan, that amount must be figured into the would-be buyer's debt load and can prevent him or her from qualifying for a mortgage.

Unlike most family gifts, DAP assistance is not free. Usually, it is sellers who provide help through these DAPs. They add the amount of assistance to the home's price, raising the house's actual cost to the buyer. But even though houses bought through DAPs often wind up being a bit more expensive, many of those home owners-mostly low- to moderate-income earners-otherwise would still be renters.

Typically, DAPs are not used on expensive houses, says Lemar Wooley, a HUD spokesman in Washington, D.C. He says that so far this fiscal year, "The median home price for homebuyers using a DAP is $119,500."

DAPs look like more than just a passing phase, as more and more buyers over the last several years have turned to these programs to help them buy homes. At the same time, fewer people asked their families for down payment help. In 1998, families were the single biggest sources of down payment assistance. That year, families helped in nearly 29 percent -- or 238,152 -- of FHA home purchases. Last year, that number had dropped to 91,372.

At the same time, the number of homes bought with DAPs jumped to 159,266, or about 25 percent of all FHA-insured homes, from far less than 1 percent of the FHA home market in 1998, or only 2,011 homes. In fact, more FHA home buyers now find they need some sort of down payment assistance than in previous years. Overall, down payment help from all sources combined was involved in 46.6 percent of the FHA-approved homes purchases as of May 2005, up sharply from 29.9 percent in 1998.

There are a number of DAPs nationwide, and most of them work the same way. There rarely is much room for negotiating in a DAP-backed sale. Sellers and builders, often as a last resort to sell their houses, start the process by going to a DAP and agreeing to donate between 2 percent and 10 percent of the value of the house to help a buyer cover closing costs, make the down payment, or both. As a general rule, the amount of the donation to the DAP is usually added to the asking price. The sellers or their real estate agents then advertise that the assistance is available.

Here's how a typical deal would work. A home that would normally sell for $100,000 might sell for $105,000. That extra $5,000 would fit within the range that most property appraisers give when they assess the value of a home. The DAP agrees to supply the $5,000 to cover the down payment and closing costs. Once the home is sold, the seller then makes a donation to the DAP-in this case, $5,000-plus a service fee. Sellers are then able to write donations off on their income taxes as a gift to a non-profit organization.

Wooley points out that buyers "should understand that if the sale price is increased to accommodate the down payment funds… in the end, the homebuyers are financing the down payment of their mortgage, and they then have no equity in the home."

Even though people wind up paying for the DAP "gift," they also end up owning a home of their own, and that is what counts. Equity builds over time as people make their regular monthly payments, add improvements and see the value of their homes increase. Everyone has to start somewhere, and a home with little or no equity is still a home, a starting point.

There are numerous DAPs. Here are four of them: Housing Action Resource Trust (HART), http://www.hartprogram.com , has assisted more than 50,000 homebuyers since it started in 1989. HART operates nationally, and tends to focus on rehabilitated homes in HUD-designated revitalization areas. Partners in Charity (PIC), http://www.partnersincharity.org , gives a portion of every seller's contribution to a charity in the same neighborhood as the home being sold.

AmeriDream, http://www.ameridream.org , helps more than 4,000 homebuyers a month, and also operates the AmeriDream Redevelopment Program which builds housing for low and moderate-income buyers, and rehabilitates older houses and then sells them. The Nehemiah Program, http://www.nehemiahcorp.org , says it is the country's largest DAP and has handed out more that $764 million to help more than 190,000 people buy homes since it was started in 1997.