The general answer is that homeopathy is not regulated in any state so anybody can use it in the legitimate course of their business. In all states, you cannot practice medicine without a license. Prerequisites vary by school. Some courses are structured only for medical practitioners. Other courses are open to any interested student and have no formal prerequisites.
Tuition depends on the length of the program.
Some schools may grant a tuition discount or private aid for exceptional cases. In the U.S., the Council on Homeopathic Education reviews educational programs. This organization is private non-profit group. Formal training can be study in an alternative school such as a school of naturopathy, homeopathy or acupuncture. There are correspondence and required-attendance schools.