Cp inner circle
You can also try nai Sarak
Nai sarak in chandani chowk is your go to place for books at cheaper prize
You can easily find all kinds of books in Tilak Nagar book market. That's near to Tilak Nagar metro station for around 10-15 mins walking and you could take rickshaw too.
CP inner circle
The Book Shop, Jor Bagh Market -
They are an independent bookstore and also send personalised messages along with the delivery if you order online. You can physically visit the store as well to buy books