if your strapped for money and cant buy from a headshop, this is a cheap and quality way of making a bong.
just buy a stem from a headshop $6-10 bucks, and burn two holes with a cigarette into a gatorade bottle or a bottle of harder plastic, dont use a spring water bottle they are to thin, burn a hole with a smoke into the top for the stem which is about the same thickness as a cig, and another for the chamber, fill with water and smoke.
Wonderland on Walnut St. is a nice headshop, a bit pricey for the glass pieces but they have a vast selection of smoking accessories. Whenever I am in Philly I always stop by. O yea, dont forget to go downstairs.