handle materials prices really vary on type. Some wood is more expensive than types of wood. bocote, laminates versus natural wood, versus stabilized, etc. In other words, looking at say, bicote, versus desert iron wood, the bocote will be much cheaper (about half). Bone is usualy fairly comparable to most natural (non-stablized) woods (stabilized is usually more expensive).
I know the bone I use in walker lock type folders usually runs me about 8 dollars for a pair of scales (1.25-50" x 4"). Color is not usually a factor (more of that depends on availablity).
As for as toughness. Bone in inlays is not as brittle as one might think. It will of course not be as forgiving as any kind of wood. It can develope cracks over time (if allowed to dry out too much, some of that depends on the quality of bone, where it came from also, etc.). I have some folders I have even dropped and it did not crack (most of the time, it can happen though). I have always loved bone as ahanlde material. but if any of you have ever worked it. it's nasty. Smells like something died, or hasnt cleaned after itself in months, and the dust is really bad for you. Thats why many old cutlers fromt he early 2oth century suffered from a type of consumption caused by bone dust.