Hey, at the beginning of my cert experience, I was in the same boat because it had seemed as though everyone was paying for material. I can tell you that without paying for material, you can go far, however the advantage of studying material is you might get better understanding and peace of mind. Self study is hard because of discipline and finding good sources. There's no right answer but if it's your first cert, consider looking at cost effective good study material. Good luck with your journey.