I just recently trained for a job as an RBT. I started with my first two clients just this month - and I have been loving it so far. Before working I had to complete a 40-hour training course ($100 online), submit background checks/fingerprints , complete an oral exam with my supervising BCBA and pass a written mandated exam (I live in Florida). This entire process took about three months before I could actually start working in the field. I also have a B.S. in psychology. I paid out of pocket for everything except the insurance credentialing - $60 - which will be taken out of my first three paychecks. It was A LOT to get started and I doubted it at first, but I am so thankful I followed through!! I can definitely tell already that a lot of the RBT skills will come in handy as an SLP/SLPA/professional.
I met my supervising BCBA at the elementary school I was working in - I actually introduced myself because I'd been looking for an RBT position - you could probably find job listings for your area online! Luckily the woman I met is expanding her company to my city and was willing to guide me through training and other newbie-RBT stuff, but other employers may want you to have it all completed beforehand. She also is aware that I am going to school for SLP, so she lets me hoard the clients with communication challenges / functional communication skills.