well, i make a point of never spending any money i havnt earned myself on my herbal hobby, but I would suggest you buy a bubbler. they are smallish, self contained (harder to spill then a bong and can go anywhere), hit like champs, and can be used as a regular bowl when you dont feel like using water. my regular smoking apparatus is a 10 in. bubbler, and it is amazing.
if you dont go for a bubbler, i suggest a mini bong. they are dirt cheap (the acrylic ones) and hit great. pretty much anything with water is a good choice.