Not to be cliché crazy, but you get what you pay for. If all you care about is the smoke, then you can dent the side of a beer can and poke some holes in it. It'll get the job done. But, if you like the finer things in life and want to make the most of your hard-earned stash, a poor quality cheap glass pipe will not be enough.
If you don't mind being wasteful, then buy cheap pipes that need to be replaced on a regular basis and take your position in our throw away society. But, if what you really want is a quality pipe that you can get a good deal on, then read along with us.