Not sure if this website is appropriate for the advice I'm seeking, but if anyone can share golden nuggets of wisdom it will be appreciated.

I work as a holistic therapist for clients with disabilities on a 1-1 basis. I have been asked to run group sessions for disabled particpants focused around this field. I was asked how much I would want paying and I have no idea how much would be the 'going rate' to ask for. I understand each locality will be different and there are different set ups with this session work type of thing. 

My role will be a freelance worker / employee. The company will supply the venue and clients will sign up through their service, then I will be paid a set amount that will increase with each paying person....Any advice or knowledge on what freelance workers charge prior to purchasing products?

help!

Thanks

Laura