Amy, depends on what you mean by 'build a darkroom'.... I built a darkroom last year by partitioning off a part of my double garage with plasterboard on a wood frame, added some kitchen cabinets and tops, put a door in with blackout additions. I didnt put in running water and a sink as that would have significantly increased the cost - this probably the biggest decision you have to make. I wash up prints and films in the utility room and carry water to the darkroom in a 5litre jar - 5l is enough to set up for 12X16 printing with a wash holding tank. I purchased secondhand a 5X4 enlarger plus lenses and other darkroom paraphenalia. I guess total expense has been £500 - £750 ukp including building costs. I now have a permanent darkroom that is easy to use whatever time of day with minimal start up and take down time.(posted 8117 days ago)