Most Hollywood movies are brokered with greenbacks. The Underground Comedy Movie was funded by greens. ''We sold vegetable choppers in malls across the United States,'' says its 23-year-old producer, Chris Watson. With the participation of such tattered pop fixtures as Axl Rose, Anna Nicole Smith, and Karen Black, the $170,000 sketch-comedy picture, which started out as Los Angeles cable-access bits in 1988, aspires to be ''a Kentucky Fried Movie for the '90s,'' Watson says. Among the bits: ''The Miss America Bag Lady Pageant,'' shot in Tijuana with bikini-clad homeless; ''Flirty Harry,'' about a cop with the mantra ''Go ahead: Make me gay''; and a Godfather parody (''The Godmother'') featuring Joey Buttafuoco. Writer-director Vince Offer, 25, admits he knows little about cameras (''We had some trouble with the buttons''), but he has learned the art of image: ''Sometimes to call casting people, we use a girl. It seems professional.'' The L.A.-based duo's salad days aren't over yet: There's still no distributor, and scheduling snafus (Smith has been sidelined by a breast-implant-related illness) have delayed completion by a month. ''Our hope,'' says Offer, ''is that we can finish in time for Sundance.''