Mary lives on a nice, quiet, typical street in Silver Spring. A nice, quiet, typical house on her block is for sale. But it isn't selling. It isn't even budging. Mary thinks she knows why.

"They are asking $215,000 for a house they only paid $120,000 for four years ago. No wonder the real estate market is in trouble!"

But Mary is not one to cluck at a problem and not try to solve it. Here's what she suggests to get the house on her street (and all of Washington's unsold real estate) moving:

"Forget that 1989 ever happened, and offer a seller what the house would have been worth in early 1988."

In terms of dollars, here's what that would mean for the house on Mary's block that's just sitting:

The house sold in 1986 for $120,000. Nearly identical houses on the same block sold for $140,000 in 1987, $159,000 in 1988 and $229,000 in 1989. The unsold house on Mary's block is on the market for $215,000. But what if the sellers dropped the price to $160,000 -- the 1988 price?

"That would still be a nice, but not obscene, profit," Mary points out. "And the buyers would still pay a high, but not obscene, price."

The tactic is not new in the world of real estate. It's called low-balling -- deliberately underpricing a house (compared with recent selling prices) in hopes that the house will move, and move fast.

Low-balling went out of favor during the go-go 1980s because buyers were almost always willing to pay the asking price, even when it was sky-high. But now that the real estate market resembles a can of ginger ale that has been left open for 12 hours, is it time for low-balling to make a comeback?

One pro thinks it may be. Marc McGee, general manager of Samuel Pardoe Real Estate, said he talks to many other local real estate agents and they don't see a trend toward low-balling. However, "a wise seller puts his house on the market at a noticeably lower price than other comparable houses if he has to move it," Marc said. So pockets of low-balling have developed, and more might soon follow.

One form of low-balling that Marc has seen involves turning over a house after a relatively short time for exactly what you paid for it.

For example, if you paid $500,000 for a house two years ago, and you aren't attracting any interest in it at $599,000, Marc would suggest dropping the price to $539,000 after one month. If that still produces nothing, Marc would then drop the price to $500,000. "It may seem like you're just breaking even," he said, but not if you consider what you would have spent for rent in the two years you occupied the house.

It comes down to how desperate and how greedy the seller is. If you haven't been transferred to Timbuktu and can wait a year for a sale, then sitting tight (or taking the house off the market and later putting it back on) will usually be the best strategy. After all, the Washington real estate market has always cycled upward sooner or later.

But if you're in a frenzy to sell, taking a 25 percent profit might make a lot more sense than waiting (and praying) for a 75 percent profit. Just ask Mary -- and her neighbors. SEND A KID TO CAMP

We're not proud here in Fund-Raising Central. We'll take contributions from anyone, for any reason. But some gifts are a little more compelling than others, because they represent more of a sacrifice for the giver. Katie Brophy of Arlington, I'm talking about you.

Katie has been out of school for one year. "I don't have much to spare," she writes. But she sent $10 just the same, to help out our camp-bound kids.

"I know what it means for the little ones to be 'free' for even a few precious days," Katie says. She speaks the truth, folks. Any other recent grads eager to follow Katie's lead?

Meanwhile, a $200 check landed on my desk from an unusual (and lofty) source: Sen. Alan K. Simpson (R-Wyo.).

Sen. Simpson wrote an article for The Post's editorial page back in March. Its title was, "Out of the Dismal Deficit Swamp." He was routinely paid $200 for his work. But he decided to contribute the dough to our cause instead.

"Even though the swamp is dismal and the deficit is dismal and my own finances are dismal, I still wish to return the check," Sen. Simpson wrote. He suggested that it go to charity. It didn't take long for the troops in our accounting department to think of Send a Kid to Camp. Thanks to all involved.

TO CONTRIBUTE TO THE CAMPAIGN:

Make a check or money order payable to Send a Kid to Camp, and mail it to Bob Levey, The Washington Post, Washington, D.C. 20071.

In hand as of June 13: $69,867.09.

Our goal: $275,000.