Gaithersbury Warehouse, 9107-C Gaither Rd., Gaithersbury (just off I-270 and Shady Grove Road). Open weekdays, 9 a.m. to 5p.m.; Saturday and Sunday, 10 a.m. to 5 p.m. 840-1182 .

"When I buy, I buy anything. Stuart buys the arty stuff," explained Allen Gerstel about the difference between his half and Stuart Astran's half of Gaithersbury Warehouse. There are other differences, too, in the two sections of this 7000-foot furniture salesroom. Gerstel's side is used office furniture, loosely defined to include Civil War files, lockers and computer cabinets as well as the more obviously useful desks and chairs. Gerstel can't resist, when he hits the government surplus and bankrupt business sales, stocking up on oddities like type trays and map files and card files. His best buys, he says, are FBI fingerprint files. Astran's side of the business is new furniture for office and home, factory seconds and showroom samples. His taste runs to chrome and oak frames, velvet and suede upholstery, usually contemporary styles, with occasional antiques. Some of it borders on the outrageous - padded bar/stereo closets, purple velvet sofas and cabinets that unfold into many-drawered desks - but there are also sedate smoked glass tables, rows of chairs suitable for office waiting rooms, and just plain nice leather sofas. As for prices, they range from one-fourth to one-half of what the furniture would cost new or retail, but since it started as expensive furniture, the new pieces still run into the hundreds of dollars, and used desks and chairs also often make it into three figures. But, as Gerstel put it, "We're a little vague on prices," which means that there is room for bargaining.