homemade cheese molds?

I have been making buttermilk and yogurt, and a few fresh cheeses, but want to move on to something more involved. Something that will complement my homebrew.

Question: Cheese molds are expensive, so what can I use to make my own? At first I thought of PVC pipe, but have read that may not be such a good idea. HDPE pipe seems like a good option, but hard to find (although much cheaper than store bought molds). Does anybody have a cheese mold that can tell me what it is made of? Anybody else using homemade molds? Ideas?

Thanks for the info.

I've used all sorts of things- empty LME containers with the bottom cut out, sour cream containers, and so on. As long as you have a way for the whey to get out (small holes, bottom cut out, etc), it should be fine.

I've got a 4" and a 6" made out of PVC pipe. I just cut it down to length and then used a 1/32" drill bit to add drain holes for the whey. Used a cheep 1/2" plastic cutting board for a follower.