JRP is basically a Barbizon clone -- a fake agency that makes all its money by charging for classes, head shots and other promotional materials that are completely useless. I'm so glad you're doing research, since it pisses me off when companies make fortunes promising shortcuts that don't exist.
Chances are you won't be able to find an agency (a legitimate one) to represent you until you have some professional modeling experience. Agencies sometimes train models, but not as often as you'd expect. For the most part, they look for people who've gone out and gotten experience without having an agent. At least 90% of the people who have "model looks" aren't cut out for the work. They either aren't uncommonly photogenic, don't take direction well, or can't overcome their self-consciousness when striking poses that range from unnatural to stupid. And most of the people who call agencies without having modeling experience aren't really interested in the work of modeling. They want to be famous or call attention to themselves, so agents can't afford to waste time with them. That's why it's so easy for fake agencies like Barbizon and JRP to make fortunes -- by preying on young people looking for shortcuts that don't exist.
Basically, an agent's job is to provide fashion clients with experienced, professional models who know what's expected of them when they show up to work. Having a portfolio showing that you've worked professionally will earn you access to legitimate agents, but very few agents will meet with amateurs. It's very rare for an agent to "discover" a model on the street and turn her into a cover girl. It might happen once or twice per generation, but it's incredibly uncommon. Most models start their careers and learn their craft at the local level before signing with agencies.
If you need experience, contact a local or regional store and inquire about modeling for print ads. National and international chain stores hire models through agencies, but smaller stores hire local talent. It saves the companies money and also enables aspiring models to build portfolios that can lead to bigger things. If you're chosen and appear in newspaper and magazine ads, you'll not only build a portfolio, but also meet photographers who work with many corporate clients. If the photographers like your work, they'll recommend you for other jobs, enabling you to expand your portfolio. And many photographers do business with model agents and it's common for agents to give weight to recommendations from photographers.
Modeling is like any other career in that you have to start at the bottom and work your way up, proving yourself at every step. But you're absolutely right that starting your career shouldn't cost you a thing. Legitimate agents work on commission and only get paid when their models do. Paying an agent in advance would be like paying $500 to McDonalds so you can work at the drive-thru window.
Legitimate agents don't need to advertise for models or recruit them at hotels or malls. There's no shortage of experienced, professional models looking for work at any given time, so why would an agent have to advertise? You're a wise girl to be cautious. If you can find a local place to start your career, you'll have access to the legitimate agencies before too long.