One option and is basically at the starting point that many people go to is a large commercial gym, example is LA Fitness...
La Fitness is a business, it's owned and run by businessmen with a minor in accounting/bean counting, you'd have to be from the east coast to get all that that means, but lets just leave it at if a process or piece of equipment was requested and does not make the company more money, then the answer is no..
LA Fitness will hire a trainer with just about any certification.. the low end training package that they offer is $25 per session (that's a 30 minute session) with recurring charges (monthly fees) so that the client can achieve their stated goals .... January is a very busy month for them.
They compensate the trainer $6 per session on a w-2 employment basis...
advantages to this is that you as a trainer show up, train and go home, you can up sell the client training and get a commission but it's nominal.. as in the client is training with you 1x per week and they want to train with you 2x week instead or an hour session... you get the idea
All other clubs will hire and split the training that is sold to the client, but often times it favors the club, and you have to bring your own clients to the club and they join the club you work at..
Some clubs will charge you a fee per client or unlimited use per month.. this can be good and bad, you still provide your own clients, however an example of this would be $13 per hour session that you charge a client goes to the gym and whatever else you charge the client is your fee... that same club could offer you $350 per month with unlimited access for you and your clients with no membership dues to the client, this is nice because if they are not with you, they don't train there..
You have to have your own liability insurance but this is normally $125-300 per year and is really nominal..
So as we can see there are many different ways to have a JOB with a club, either employer/employee, sub contractor, or contracted space (much like a hairdresser will rent a chair, or a stripper will pay to be in a strip joint, then she keeps all the $$$ she gets)..
I'll post more in a bit..