Most schools and coaching institutes (Kota, Allen, Aakash) have a library. Borrow the book for 2 weeks. Use your phone's scanner app (like CamScanner or Adobe Scan) to digitize only the chapters you struggle with. This is legal for personal use (fair use policy).
There are several ways to access RD Sharma's Objective Mathematics PDF for free: objective mathematics rd sharma pdf free
Don’t let the search for a free PDF become a procrastination tool. Your future IIT seat is waiting for you to solve that first differential equation—whether on paper or a screen. Most schools and coaching institutes (Kota, Allen, Aakash)