First of all, what is the appropriate newsgroup for questions about stepper motors? On with the actual question:
Is there a reasonably priced option for driving stepper motors smoothly, i.e., not having them stop and start every 1.8 (or 0.9) degrees? I have some 200 step/rev motors that I would like to drive at speeds ranging from 0.1 to 4 RPM in one application and 0.4 to 16 RPM in another. I would prefer a system that has already been designed by someone who knows what they are doing, though I would not mind doing some kit assembly.