Never pay consultants for grant writing work with a percentage of the grant award! It is inappropriate, even unethical, to do so. This article from The Grantsmanship Center gives an excellent explanation as to why paying consultants this way is wrong. It still surprises me that people ask me about this quite often. Clearly, a lot of confusion remains out there on this topic. I discussed this in my course on Consultant Grant Writing Contracts that is featured on Nonprofit.Courses site, but this article goes into more depth. For anyone who still has questions about using a contingency fee for grant writing work, this article will help you. It also has some good guidelines for consultants to use to set their fees.