Plant lighting will be a significant fraction of the overall costs of a bioregenerative life support system on the Moon. Equivalent mass (EM) for lighting can exceed 35% of the system total with all-electrical lighting. In this paper, variation of cost factors related to lighting is addressed for various options including fluorescent, high-pressure sodium, LED, and microwave lamps. An attempt is also made to quantify the cost of using sunlight, considering collectors, optical fibers, and diffusers. The results show that use of sunlight is important in reducing cost for a lunar base because of the difficulty of heat rejection with electrical lighting during the lunar day.