When the campaign staff of Virginia attorney general candidate W.R. (Buster) O'Brien looked at television advertising time O'Brien might buy this fall, the Sept. 9 Redskins-Cowboys football game seemed like a sure winner for audience ratings in the vote-rich Washington suburbs.

But the cost for a 30-second TV spot was $25,000. "We didn't consider it at all," said Jeff Gregson, O'Brien's campaign manager, who's still mulling over his options.

He sighed at the cost of other Washington market TV programs: $6,000 for 30 seconds on "Dynasty" or "Hotel," $3,000 for "The Love Boat" or reruns of "M*A*S*H," prices 10 times the costs of similar ads on stations in areas of Virginia farther from metropolitan Washington.

Despite the grumbling by O'Brien's staff, the high cost of Washington television -- now considered crucial in any Virginia political campaign -- has become a driving force pushing Virginia's political candidates toward record-setting fund raising this summer. And while beach-going Virginia voters are tuned to nearly anything but politics, media decisions are being made this summer that some politicians say will make or break a campaign in the fall.

A record $7 million already has been raised in the races for governor, lieutenant governor and attorney general, and most of that was used just to get through the convention nomination stages last month. Democrat Gerald L. Baliles and Republican Wyatt B. Durrette, the state's gubernatorial candidates, are each easily over the $1 million mark in their campaigns for governor.

National political consultant David Doak, who is advising Baliles, said his candidate is spending 60 percent of his time this summer on raising funds.

But even in Virginia, where there are no limits on how much individuals, corporations or groups may give -- and state parties don't even have to report what they get or spend -- some political operatives are wondering if the state's monied interests can sustain the flow of dollars this year.

"There's only so much money out there," said state Del. Alson H. Smith Jr. of Winchester, a key fund-raiser for Democratic Gov. Charles S. Robb, who under Virginia law cannot succeed himself.

Campaigns hire expensive paid staff to do what volunteers once did and spend thousands on sophisticated mailings. Telephone and communications costs have skyrocketed, and high-priced consultants -- once scorned as "outsiders" and "hired guns" -- have become the norm. When Durrette recently dismissed his campaign manager, Michael Conlin, he gave him a bonus of $10,000 for helping him win the GOP nomination -- a fraction of the salary that the typical campaign consultant will earn this year.

"It's turned into a big business," said Gregson, a veteran of several state campaigns. "The two top things are fund raising and media," he said.

"It used to be that nothing at all happened before Labor Day . . . , " said Fairfax County developer John T. (Til) Hazel, who personally gave $100,000 to Republican Rep. Stan Parris' unsuccessful bid for his party's nomination for governor. "It has particularly changed . . . by the need to make media commitments with checks up front."

"We all recognize that political campaigns have become very expensive," Hazel said. "If you keep your pocketbook in your pocket, you don't have much reason to believe anybody is going to listen to you."

A review of recent campaign reports showed that some of the current candidates depend on individuals, such as Hazel, or groups to finance many of their early costs. No one, however, has exceeded the largess of Robert G. Moore, a former truck driver who made a fortune in Virginia Beach development, who this year has given a total of $323,500 to several candidates.

Fund-raisers for both parties have said early estimates that each party would raise another $3 million for the Nov. 5 general election are unrealistic and that their goals are closer to $2 million and the amounts spent in 1981.

State Sen. L. Douglas Wilder of Richmond, the Democratic nominee for lieutenant governor, has cut his expected goal in half -- to $500,000, an amount closer to the costs of 1981 races. The campaign of Wilder's opponent, Republican state Sen. John H. Chichester of Fredericksburg, also has backed away from expectations that he would raise $1 million in cash.

O'Brien and his opponent, Democrat Mary Sue Terry of Patrick County, are sticking with estimates of $750,000 to $1 million for their attorney general campaigns.

Two candidates for governor who lost their nomination battles, Democratic Lt. Gov. Richard J. Davis and Republican Parris, each spent about $1 million.

One other unsuccessful candidate got an expensive introduction to Virginia politics this year. Richard A. Viguerie, the nationally known conservative direct-mail businessman from Fairfax County, was making his first bid for state office in the Republican race for lieutenant governor.

Viguerie, who billed himself as the most conservative candidate in the race, ironically rang up the largest debt.

He spent a total of $696,685, with $458,586 coming from his Richard A. Viguerie Co. in Falls Church, and reported outstanding obligations last week of another $364,899, including a $186,000 loan to his campaign from his own company.

His campaign report also showed that Viguerie failed to gain much advantage from his presumed direct-mail fund-raising ability, reporting only about $70,000 in outside contributions.

Viguerie, who lost the GOP nomination to Chichester, declined to comment on his fund-raising tactics.

The search for money can have its drawbacks.

Terry's campaign for attorney general recently hosted one of the biggest fund-raising events so far this year. Coal barons and other business leaders who were flown in on nine private planes plunked down $5,000 a couple to dine with Terry in the scenic, far southwestern mountain region of Wise County.

Terry took in $85,000 and is still counting checks coming in.

But the fund-raiser, months in the planning, left a sour taste among some local Democrats, including the county party chairman, who was not invited to the dinner even though his car was used to transport the upper-crust guests. It was "very, very inconsiderate and rude," chairman Glenn Craft was quoted in the Coal Field Progress newspaper.

A Republican legislative candidate has seized on the little flap in his own advertising for a $25-a-plate fund-raiser. "We won't serve quail and oysters, but then we won't charge you $5,000 . . . , " the ad reads.