In my experience it is only the very large full time RDA centres that pay people for their involvment with the RDA. Most groups rely on volunteer power to keep the bank balance happy. One of the groups I work with has a physio, she is a volunteer like the rest of us and has a job elsewhere doing physio.
My recommendation to you would be to go into a career that you can use the skills to support the RDA, eg physio etc, and that gives you the flexibility to donate time to the RDA as a volunteer.
I'm a trainee teacher and use the skills and experience I gain in the classroom to make myself a better RDA Instructor in my spare time