In response to costs for building a darkroom, I recently spent about $2000 on mine. I painted floor and walls, put in an 8-foot fiberglass sink and plumbing (I already had hot and cold water outlets stubbed in, but had to install faucets and pipes), two 3x3-foot cabinets on the walls, an 8x4-foot work surface (covered with formica) on the opposite wall with a 4-drawer cabinet underneath and various shelves for paper, 4 8-foot shelves on each wall, a corner set of narrow shelves for chemicals and mixing, and a combination UV light exposure unit and drying cabinet. I already owned two enlargers, timers, trays, scales, a print washer, etc., but I had to purchase some additional safe lights.