I smell a rat.
There are other ways in obtaning funding for those who can not afford the fees.
It's akin to another type of business, for example, a clothes shop for school uniforms asking other customers to pay a little extra in order to kit out the child whose parents can't afford the cost of the uniform.
That's why we have services (such as the health visiting service and social services) and grants available, to help people in such circumstances.
You have no guarantee that the extra fee you are willing to pay would really go to fund another child. I would be worried.