Here in Missouri it is perfectly legal to sell a "water pipe" it is also perfectly legal to sell a "glass pipe" you can also legally purchase these things and own them freely. However it is highly illegal to sell or own a "bong" because "bong's" are used to smoke weed. Water pipes are used to smoke tobacco. This is why in Missouri if you go to a head shop and ask to be shown that sweetass bong on the second shelf you would be promptly be told that they do not sell bongs but they will show you the water cooled tobacco smoking accessory you have pointed at.

I believe that Tommy Chong was indeed selling "bongs" on the internet.