The word on the streets -- streets like Sunset Boulevard and Rodeo Drive--is that the networks, especially NBC, are on the lookout for cheaper prime-time programming, hoping to hold on to viewers by cutting down on the number of reruns in the months ahead while at the same time avoiding wild splurges on expensive shows. Home Box Office, after all, programs 12 months a year, and the networks groggily are beginning to realize that.

However, they will have to do better at cheaper than NBC does tonight with "Prime Times" at 9 and "Famous Lives" at 10, both on Channel 4, both anything but lavish and neither quite as compelling as the table of contents on the cover of Reader's Digest.

"Prime Times" starts out rather promisingly and then turns into a flagrant case of clip abuse. The clips are from old TV shows and they are used in specious or spurious ways to wring a snicker or two from the old reliable laugh machine. The executive producers, Andrew Solt and Malcolm Leo, tried the same trick with campy B-movie clips in the theatrical feature "It Came From Hollywood" and they fell flat uponst their faces.

With "Prime Times" they land on approximately the same place. A few more brainstorms like this show and that movie, and the faces of Solt and Leo could compress veritably into pancakes. That is, their faces could become as one-dimensional as their concepts.

At least "Prime Times" acknowledges that television has a past, a past crowded with oddities and curios that could be assembled entertainingly and even enlighteningly, in one crazy way or another (in a show perhaps called "That Passed For Entertainment"), but here are slapped together to flimsy purpose. TV's history looms enormous in the shared consciousness of post-war boom babies, and "Prime Times" triggers some happy, wacky or even endearing memories, but it tends to trash the good vibrations with arch tricks.

Leslie Nielsen is the host, genial as can be, and the program opens with a cute editing exercise that has him being chased by a variety of TV cops, from Starsky and Hutch to the SWAT team to Officers Toody and Muldoon of "Car 54, Where Are You?" Nielsen tells viewers, "We're willing to try almost anything to get your attention," and that proves all too true.

One segment suggests what the program could have been. It traces social attitudes toward sex as reflected in TV sitcoms, starting with a scene from "Leave It to Beaver" with Jerry Mathers and the late Hugh Beaumont ("Dad--about girls . . . "), progressing, if that is the word, through "Bachelor Father" and "Gidget" and on to a discussion of "the pill" in a 1978 "Fish" and a father's farcical reaction to his gay son's desire for a sex change operation in an early episode of "Soap."

Excuses for sketches on the program lean toward the lame, but the odds and ends from TV's crowded closet perk things up from time to time: the cast of "Bonanza" singing words to the show's rousing title tune (this is cut unforgivably short); Orson Welles crooning stentorially to a boatful of kiddies on a forgotten "Shindig"; a young James Caan and a young Martin Sheen in an old "Route 66"; and an even younger Linda Evans on an ancient "Ozzie and Harriet."

The clips left alone are the most effective. Those toyed with and gimmicked up (Nielsen is electronically interpolated into an old "Dragnet" scene, for instance) are just irritating. The show benefits from an arresting opening credit collage put together by Jerry Kramer and Associates.

"Famous Lives" is a Barbara Walters celebrity interview hour without Barbara Walters but with Wayne Rogers. He is out of his element, but then, his element--light comic acting--is only a stone's throw from this show's element, fatuous interviews with "stars" whose paths are strewn with palms because they are making lots of money at whatever they are doing.

Tom Selleck, first interviewed, is "an extremely likable, handsome man," Rogers goes so far as to say (wow, what candor), and Selleck, before denying that fans drive by his home throwing their underwear onto his lawn, says, "The local people in Hawaii are quite respective of my privacy." Stefanie Powers, next up, is asked if animals make a good substitute for children. Of the late William Holden, with whom she was romantically linked, Rogers says, "His work was interrupted by his death." Such often is the case.

Magic Johnson, the third interviewee, comes off best--unpretentious, genuine, a big-hearted sparkler. "I go crazy, I light up" upon winning a basketball game, he says. For some odd reason, his segment includes the hour's second clip from "Hart to Hart," the Powers series on ABC, but it is attractively bracketed by shots of Johnson making layups that have been enhanced with the electronic shadow effect used so effectively on last year's Shirley MacLaine "Illusions" special and on various rock videos.

Last and loudly least is Jack Klugman, star of the canceled "Quincy, M.E.," and Rogers says of him, "At age 60, Jack seems to have found contentment." Oh good. We were so worried. Wayne Rogers is perhaps to be congratulated for making Barbara Walters look profound, witty and practically investigative, and "Famous Lives" is one for the dustbin, not the time capsule.