Ghetto Fog Machine

If you're on a budget, you can cobble together a good-enough fog machine using a large candle, an aluminum pie plate, a soda bottle top, a gallon of distilled water, and a small bottle of glycerin

Mix a solution of one part glycerin to three parts distilled water—this is your fog juice. You should be able to find glycerin at your local pharmacy for a few bucks.

For the fog machine itself cut the top off a 2-liter soda bottle and tape to a small aluminum pie plate. Place this on top of a lit candle (a large one with multiple wicks is best) and add a teaspoon or so of fog juice, which should be enough to fill the room.

When you want more fog you'll have to pour in another teaspoon of fog juice.