See to be frank there is nothing free of cost. You need to invest your money and time with hard work in things that you wish to pursue. The books like textbooks and reference books, objective ones will cost you. You might borrow it from someone but it will be outdated. The money is nothing compared to that you will be spending on coaching. So books are kind of free.

NCERT books you can get from website in the form of ebook. NCERT forms the basis and most important part in preparation which you are getting free. Other books you need to buy. Self study requires no money but lots of hard work. So get started.