6x24" BL bulbs in a plywood box. The fixtures, bulbs and light switch (fixtures are wired to switch) cost around $100. The plywood was scrap so it was free. It seems to work fine, but I've only made 30 or 40 prints so far in Van Dyke and Cyanotype. I left enough room for another 2 bulbs just in case I ever want to make huge prints!