ok, i think we're referring to two diff kinds of speed. the pure stuff which usually comes in rock form, and the "other" stuff which is a powder. Any given powder could be just uncut, crushed rock (but that's unlikely, why would anyone crush & not cut??) - i think when you get offered cheap speed it's just heavily cut down, and the expensive stuff is closer to pure.
on another point (dumb pun hehe) i'm interested to know people's opinions on something - is rock the purest form of speed? In my experience it's the most potent, but I don't know much about the manufacturing process. I had someone try and tell me that speed, in it's purest form, is a sticky syrup-like formula and NOT rock, and bakers, dealers, whoever, just soldify it for the purposes of sale or storage.
????