i had a bolex 16mm for film school last year. the school provided it for me and i bought it off of them for a lot of money.
normally you can buy them through local dealers. in montreal (where I went to film school) there's a ton of dealers. but here in ottawa where i live/grew up, not so much :S
it really depends on where you live and how readily available that stuff is to you. you may have to go searching online even or special order it through a smaller camera shop.