As per my suggestion you will purchase Parag Gupta Sir Book (Both books problem and solution) and prepare from his class notes and dont forget to do all the questions from ICAI study mat and practise manual and RTP and MTP
for basic concepts( which beign with relevant costing actually 90 percent final costing based on this topic. ) refer Sanjay Aggarwal class notes. Costings books in market very cumbersome which may lead confusion.So it is better refer said notes before starting it with any book.
Paduka... I am following it
I am also on self study and same attempt
Although presentation is not so good but concept are properly explained with lots of problems.
But if u want better presentation than go for Sanjay Agrawal.
Best of luck