I teach lay responder CPR/FA/AED, Professional rescuer CPR/AED, Blended learning for all CPR courses (essentially just a bridge certification to you can teach classes that have an online segment), Lifeguarding, and Babysitter's Training (BLEH it's a terrible class to teach!).
I am currently employed by the Red Cross, so all of my certifications were paid for by them. If you were not employed or volunteering for the Red Cross and just pay for the certification to teach, you become what's known as an "Authorized Provider". Essentially, you teach the course as a separate entity, and can charge whatever you want for the class, and pay the Red Cross like $8/person/class for registration into their database. This is a good path for many city/town rec centers as they frequently hold community classes that you would then be certified to teach.
At present, Babysitter's courses are at a high demand, as are lifeguarding classes. If you were an Authorized Provider for one/both of those classes, I have no doubt you could find work in recreation centers as a contracted instructor!
