When they bid for a house in Potomac in April, Nicole and Bryan Kustner did everything their real estate agents recommended.

They agreed to a contract clause that escalated their offer $140,000 above the $825,000 asking price. They threw in a big down payment and a large deposit. They wrote a "very nice letter" to separate themselves from the pack.

"We advise all our clients to do that," said agent Jason Volat.

"The thing that slam-dunked" the Kustners' offer over a dozen others, however, was another extra that's becoming more common: They let the sellers stay on in the house for two months, free, said Volat, who works with partner Melina Tsantis at Weichert Realtors in Cabin John.

Even as speculation builds up about how long the frenzy can last, the competition for housing has gotten so heated that buyers are routinely going to extreme lengths to grab the golden ring, or the golden Colonial, agents say.

The war has moved far beyond stripped-down contracts with few or no contingency clauses, where bidders waive almost anything that might hold up the deal, including home inspections and appraisals.

It's gone beyond gushy letters, where bidders declare they have fallen deeply in love with the properties or offer tug-at-the-heartstring snapshots of newlyweds, babies or dogs.

Some bidders have thrown in a case of wine, a two-week stay at a Cape Cod beach house, a seven-day cruise to the Bahamas and season tickets to the National Symphony Orchestra. But even these are often no longer enough, say agents.

The "bottom line now is just about the money," said Cheryl Hanks of W.C. & A.N. Miller Cos. in Chevy Chase.

Three times last year, Hanks allowed her clients to offer sellers a two-week stay at her Cape Cod beach house. "It didn't work," she said. Sellers are commanding such high bids and lucrative contract terms that they don't pay much heed to such gestures, she said.

Two weeks at the beach doesn't seem all that exotic a lure, she said. "Why, they could afford to stay the whole summer with the money they're getting for these houses."

The Bahamas cruise, said David Ridley, managing broker at Samson Realty in Chantilly, was a recent client's idea: "He'd heard it had worked in . . . San Francisco."

The boat ride didn't float, either. Another bid came in higher, Ridley said.

Anita Murchie thinks a case of expensive wine distinguished her bid from others when she bought a rental property in Alexandria. Her husband, Gordon, is president of the Vinifera Wine Growers Association and executive director of the Virginia Wineries Association. Murchie said it made sense to make the offer "because we had seen that the people who were selling . . . had a small wine collection, and we were in the wine industry."

New Jersey resident Karen J. Shapiro says her recent unsuccessful bids on three houses in American University Park and Chevy Chase, D.C., proved to her that contract creativity doesn't work unless it involves the most cash.

The interior designer offered not only to waive contingency clauses and to submit escalator clauses taking her bids almost $100,000 above listing prices, but she also tried to increase her contracts by $1,800 or $3,600 at a time in the escalator clause in case the sellers were Jewish, as she is. Eighteen and 36 are references to the Hebrew word for life and considered positive.

In one case, Shapiro and her husband also submitted a letter promising to showcase a house in the upscale magazine Elle Decor.

"We wrote letters on three of the four houses we looked at," Shapiro said. But for one charming property, she described how "Elle Decor was interested in picking up the story . . . of how I'm going from being a suburban designer to being an empty nester."

Shapiro said she thought the sellers might be struck by her plans to make over their house: "People love to tell stories about their houses. . . . We thought, 'Let's just see if they're going to be impressed that I would make it absolutely fabulous.' " However, she continued, "nothing but money is enough" to sway Washington sellers.

"The buyer is really treated like garbage," she said. "It was a horrific process."

Stephen Israel, president of Buyer's Edge Co., a buyers' agent brokerage in Bethesda, said he has tried variations on gifts, including the season tickets to the symphony. That one worked.

He declined, though, to reveal what else he has tried. "The best buyers' agents out there have a number of strategies. And I'm not going to give them up," he said.

But he is among those who say that wine or waves pale when compared with the power of cash.

"I guess if you have a really great summer house, it might still work," Israel said, "but how many people have a house on the beach in Antigua?"

Instead, agents say bidders increasingly offer more money above the listing price, as well as contract terms that promise the equivalent of more money.

"You lose four houses, you'll do whatever you can to win. . . . But in the final analysis, there are only two issues that matter to people. One is money and one is convenience," said Marj Rosner, manager of six Long & Foster offices in Northwest Washington.

Cash incentives in the contract include generous escalator clauses, where the buyer promises to pay $2,000, $5,000 or whatever above any other offers. Ridley, the Chantilly real estate broker, said he has heard recently of "unlimited escalation addendums," meaning no ceilings. The bids keep going up until somebody cries uncle.

Rosner said some buyers are offering six or seven months of free rent to sellers. "Letting sellers stay till the end of this calendar year, that gets people's attention," Rosner said.

A fat earnest money deposit on a house, written to a settlement attorney or other third party to be held in escrow account until settlement, also wins points because it shows the seller how serious a buyer is.

Money that's held in escrow, however, can remain in limbo if a deal goes sour. So writing a fat earnest money deposit directly to the seller, rather than sending it to escrow, is a new twist that's even better as far as sellers are concerned, some agents say.

Two Army doctors stationed in South Korea recently won the bidding on a house in Northwest Washington in part because they agreed to include a $40,000 non-refundable check in their $887,000 offer, which was well above the listing price, said agent Kathi Higdon Kershaw of Long & Foster's Kentlands office.

"We were apparently neck-and-neck with another offer," Kershaw said. "We got it because, one, the other agent didn't bother to show up in person with the contract presentation, and, two, because of the non-refundable check."

The check, sent directly to the sellers' address, "made the sellers feel comfortable that the offer would stand up," Kershaw said. Because the couple, both Army majors, had never seen the house, the sellers might have worried that they'd walk away when they came back to Washington this month, Kershaw said.

Personal letters are popular in some circles, but not others.

For instance, Rosner said, she is concerned that letters might violate fair housing laws and prompt lawsuits. She says she tells buyers' agents not to submit them. She recently was organizing a list of offers that were to be presented to the seller of a Falls Church house. She threw out letters that were attached to three of the four offers before the seller ever saw them. "I think it's inherently discriminatory" to show letters that contain photos or describe buyers, Rosner said.

Others say they allow or encourage letters because it's up to the sellers to decide which offer to take.

Denise Champion, a Long & Foster agent in Chevy Chase, suggested to one young couple that they draft a letter on a Shepherd Park house because she thought it could make a difference.

Her client, Nadine Duplessy Kearns, thinks the personal note she wrote helped persuade sellers Bob and Elaine Joost to pick her family's bid before a scheduled open house in October. "When the seller opened the letter, she smiled and said, 'That's my buyer,' " Kearns recalled.

The letter detailed Nadine and Curtis "Andre" Kearns III's great desire to move from Arlington to the District, where Andre grew up, and their interest in the local schools and a nearby church.

"This is a great neighborhood for a young family like ours," wrote the Kearnses, who have a toddler. They also wrote about how much they loved the house's library.

"The library was it for me," Kearns recalled.

Elaine Joost said she was impressed with the monetary terms of the offer, which was about $11,000 above the listing price. "And since we weren't interested in drawing every last cent from this property, we saw no reason to wait."

But the letter, and its reference to the library that Joost treasured, struck home, she said.

"We wanted . . . to find someone who would be as much a part of the neighborhood as we were. . . . We didn't want to sell to someone who would do a quick slap and dash of paint and then resell, or who would . . . jack up the car and blast their speakers," Joost said.

Casey O'Neal, an associate broker at Re/Max Allegiance, said letters are "more of the exception than the rule in this market."

But, personal messages can still make an offer stand out, he said. He provided one note submitted to his Arlington sellers last July by fellow agent Debbie Wicker.

"I work for the State Department, and have been overseas for the past twelve years," wrote Steve Walker. "The last five years have been especially difficult ones for us: I was assigned to Yemen, and then to Syria. My family was evacuated three times during this period (with one evacuation lasting nine months)."

He added, "One of the things that got us through this difficult time of family separation and dicey security situations, was imagining our return to Washington, and buying our first home where, after long last, we could put down some roots."

The emotional pitch worked, said O'Neal -- but only in combination with the family's strong finances.

"We've had people take pictures of themselves, their babies and their dogs," O'Neal said. "But really what it comes down to is their financial strength. That's ultimately what seals anybody's deal."

Nadine and Andre Kearns sent the seller a letter about their family.

Andre and Nadine Kearns with son Julien, 18 months, moved into their D.C. home in November. They wrote the seller a letter about their desire to move to the District, where Andre grew up, and their interest in a nearby library.