> Charge less the first time, charge some more the next time (if their happy)

I doubt if that will work. What if they were happy because they got quality output for less money? How would you now go to them and say that I gave you a discount the first time around and now you have to pay the full price? If you did not make it clear up front, you will have a very unhappy client.

I think it's incorrect to assume that everyone hires consulting companies to cut costs. Some folks hire them because they do not want to build IT team. Some folks hire them because they need some work done for the quarter BUT won't be needing them on permanent basis. In such cases, it's not about the cost but paying right amount of money to get their work done.