Freelancer relocation agent expected fees - help!

I have been looking into becoming a Freelance Relocation Agent in Belgium and am totally clueless what fees I could charge. I am getting in discussions about a position working as a freelancer for a relocation agency here and need an idea on what I can charge. I don't want to go to high and scare them off, but equally don't want to undercharge and get stuck there.
Can anyone give me any sort of advice/clues as to fees that consultants charge in that area please?
I would really appreciate it!
Thanks