Hmmm this is a loaded question
I say any penny you pay a consultant is too much! J/K
Actually I have seen consultants charge from 600/per man day to 30K for the year to help them implement a system. I guess what it boils down to, get what you can from where you can. If you know a company with deep pockets can afford to pay more than charge them more (I know that sounds unethical, but who said consultants had any ethics. Once again JUST KIDDING!) and on the flip side cut the smaller companies some slack. I think Hfowler was pretty much right on most charge 800-1600 per man day plus expenses.