It is to be cleared first that the FPM course is completely equivalent to a Ph.D degree. It takes approximately 4-5 years to complete, along with accurate learning and research work.
The fact is that ISB generally pays Rs. 40000 as a stipend along with House Allowances to the candidates who are doing FPM on a full-time basis. Thereby you are not required to pay anything from their own pocket, but they can earn 40 thousand per month.
However, the most important thing is that FPM requires accuracy to complete the study without spending money. So, you have to study with full accuracy, and earn support from this institute to carry on your personal and family expenses. You have to enroll as a full-time candidate and should not have any other source of income.
If you have any other second income, then it will not work. After completing this program, the student will get unlimited rewards, considering their knowledge and income.