Nothing is free anymore - not even, it turns out, the privilege of joining hands with Howard Jarvis to raise Old Ned about your high taxes.

Jarvis is the 76-year-old Los Angeles man who orchestrated the California property tax revolt. Flush with the success of Proposition 13, he is going national.

Last night, in 162 television stations around the country, he invited the presumably angry masses to hook up with him and fight to get those high federal taxes reduced.

Never mind that they charged no admission to the Boston Tea Party Times change, and this time around there is a price tag on being a tax rebel.

Jarvis' American Tax Reform Movement, the sponsor of last night's halfhour polemic, is hawking memberships at $25 apiece. One hundred dollars will land a contributor a seat on ATRM's national policy committee, an undefined entity.

The money Jarvis vowed, will go to ward building "the largest tax organization in this country." And the commercial noted, $25 is not all that much to buy a plan that will save a contributor "thousands" of dollars year.

The plan is not that difficult. Jarvis said his aim is to cut every family's income taxes by 25 percent. Beyond that, he would cut the maximum tax rate on capital gains from almost 50 percent to 15 percent.

And then what?

The idea is to cut the budget deficit, stimulate employment, balance the federal budget and strengthen the dollar by simply slashing the fat from federal programs, Jarvis explained.

Yes, but then what?

Jarvis said he would leave the details up to the 100 senators and 435 members of Congress. "They can do it if they will . . . We need to put their feet to the fire," he said in a rash of optimism.

Short on detail Jarvis might have been, but there was no mistaking the indignation of taxpayer-on-the-street commentaries on ATRM's prerecorded film.

One after another, they ralied at the extravagences of government spending and bemoaned the big tax bite in their paychecks.

As if to authenticate the high dudgeon, all all-star cast of conservative economic commentators joined in endorsing the Jarvis pitch.

Dr. Neil Jacoby, a UCLA professor, testified that Proposition 13 is working in California and restoring popular faith in democratic government.

Milton Friedman, whose thinking earned him a Nobel prize, said the Jurvis plan will work for America.

"Your plan is sound," said William Simon, secretary of the treasury in the Nixon and Ford administrations. He warned that bureaucrats in Washington "only want more control over our lives."

Well, now, Simon is a bona fide critic of excessive governmental spending. But then he also is remembered for his overseas travel with handsome entourages that cost taxpayers more than $500,000 in his last 18 months as secretary.

Even more oddly, perhaps, the tone of the whole program was that Washington, where WTTG-Channel 5 aired the show in prime time, is awash in the most profligate kind of fiscal zaniness.

For a brief while, it seemed that Jarvis was only rehashing the Golden Fleece awards handed out monthly by Sen. William Proxmire (D-Wis.).

A big jet plane leaves the runway - congressmen off on a junket. A sweaty tennis player swings his racket - that's a federal study on tennis court rudeness. An egg fries in a skillet - study on the time it takes to fix breakfast. And so on.

"That's the tip of the iceberg," said Jarvis. "The only way to reduce spending is not to give the money to government in the first place."

Jarvis said he was going national with his tax-cutting campaign because "the momentum of Proposition 13 must not die . . . We must not let the politicians cover it."

Master of ceremonies Robert Reed (Mr. Brady of TV's "The Brady Bunch") didn't have to ask very hard to get the right answers from Howard Jarvis.

The lessons of the 2-to-1 vote in California last June for Proposition 13, slashing property taxes, can be applied nationally, Jarvis said - with no pain to anyone but the people who spend the money.

"We want to cut the fat at the top and not the muscle at the bottom." Jarvis said. The idea is to give public officials "a new, important job - to locate and eliminate waste."

He may be attacking faceless Washington, but to beat them Jarvis must figure he has to join them. Contributions to ATRM are to be sent, according to the ads, to a post office box in . . . Washington, D.C. CAPTION: Picture, HOWARD JARVIS . . . hawking memberships for $25 each