In order to make a cheap water bong you need a 20 ounce water bottle, a Bic pen, gum, aluminum foil and a straight pin. First, cut a hole in the bottle. This hole should be big enough to fit the pen shat through. Stick the empty pen shaft through the hole angling it down so it touches the bottom of the bottle. Take your gum, chew it!, and press it around the pen shaft near the hole. This will seal the hole and pen. Cut another hole, about 1/4 inch, across from your first hole. Take off the bottle cap and place it on the top of the pen shaft. Now, take foil, wrap it around the pen shaft and cap at the same time to make a bowl. Poke holes in the foil and this will now act as your filter. Fill the bottle up with water about an inch below the pen shaft. You have now created a cheap and easy bong. Enjoy!