Yea. It can cost 100's to join a youth league. Pretty sure the academies are free though, but that doesn't stop them from making money.
Whoa, you're waaaaaay off.
If you're talking about the recreational level, then yes it only costs about $100 or so to join a league. But as soon as you start playing at the competitive level the club fees spike substantially to $1500 - 2500 per year. This doesn't include tournament fees and travel, which can be an additional $500 - 1500. Some clubs still make you pay for your own uniforms and gear on top of that so that's another $300-400. And then there's additional costs of private training ($80 - 100 per hour), which the clubs should be providing for free. If you're playing at the elite level of soccer, you're easily paying over $5,000 per year often a lot more. Even kids who play on "B" teams at the competitive level are still paying at least $2,000 per year.
That's for competitive club teams. Then you have Academies and there are about 100 academy programs nationwide. Those can cost 6,000 - 10,000 per year, depending on the travel. The only academy teams that are actually free are the MLS funded academies (only 20) and maybe a few other small programs. The MLS academies are so spread out across the country that only the tiniest fraction of players even have that as an option.
This is what people mean by "Pay to Play". If you're a upper middle class kid, then you have the opportunity to work your way up the youth soccer development pyramid. If you're a middle class kid, it's going to be a tremendous struggle and hardship on your family to keep up. And if your lower middle/ low income family then it's pretty much impossible to get beyond the recreation/AYSO level. Sure some clubs offer scholarships but you pretty much already have to be a stud who can help the team get immediate results. But if you're a small kid with a lot of potential and natural touch but still a bit rough around the edges, you'll almost never get a scholarship. Our "Pay to Play" system doesn't care about long-term potential.
The reason people in the know rail against Pay to Play is because it prevents us from properly leveraging our large diverse population. It also creates "country club" players who are sheltered and comfortable, and don't play with the same passion and hunger as maybe someone from a different economic background and soccer culture. You end up with guys like Michael Bradley.