I just started making my own scales. I recommend starting in wood. You should be able to get some walnut cheap, and wood is easier to work than bone. Even if you end up trashing every wooden set you make, you still save on all the bone you would have used practicing. It really isn't as hard as you would think though. I have made 3 sets using just a pocket knife, hammer, sandpaper, wire cutters, and the materials for the scales and pins.

Drew