One is a completely non-profit organization, but since you say it is a training institution, it is estimated that it is not a non-profit organization.
The second is the distribution of advertising fees. Some businesses need to spend money on advertising, so they use advertising fees for free publicity, and finally they have to charge.
The third is to pass on the charges, such as selling fitness equipment, or providing one-on-one service, drinks and tea, and annual cards and monthly cards. There is always a charge.
Merchants can't do business at a loss, there will never be a free lunch, and there will never be a pie in the sky.
This is the reason, so each has its own management style and each has its own fortune. As long as you are your fitness instructor, there will always be people who need paid services, and you may not be able to learn something for free.