The first thing you need to do is gather all the parts you need. For this instructable, you will need 1 Eveready Industrial Flashlight, found at Home Depot for $3.97. You will also need 1 6V flashlight bulb from Radioshack; model KPR112. This is about $1.50. Finally, you will need 3 123 batteries. These can be found on surefire.com for about 2 dollars a piece. Total cost for this project is slightly over $10.50.