Rather than looking for a free seminary, why don’t you talk with the vocation person of your diocese and/or several religious communities. Many dioceses and communities have ways of helping those who cannot pay for their own education. My own community (Missionaries of the Most Precious Blood), as an example, if the person demonstrates that he cannot afford the education, will help set up a student loan while the person is studying. Then if the person leaves the seminary, he is asked to repay the loan when he can. However, if the person is ordained, the community will pay the loan.
I know of dioceses and other communities who also have similar programs.