Well, it would be impossible to study anything abroad for free of cost. MBBS abroad(?)could be more costly. First of all, you have to figure out the country where you want to study, then exams you are required to give and then the scholarships you can avail. It's less likely to make the whole process free of cost even with full scholarships.
And as far as your desire to become a Neurosurgeon is concerned, it shouldn't be a concern of now. Take one step at a time.
Priya Pathak, studied at Bachelor of Medicine and Bachelor of Surgery Degrees