Sorry, I am not interested in the group buy but if I may suggest, the lectures by nptel are way better and free. I have cleared gate CS 5 years in a row and always got less than 500 rank and 50+ score just by going through nptel videos and practicing the relevant books mentioned. (Didnt join because I only wanted IIT Bombay CS which ends at 150 rank) ..
For clearing product based companies I would suggest finishing the exercises in major CS topics like, Computer architecture, OS, data structures and algorithms (do CLRS book) ..
You can always PM me if you are stuck at a specific topic and stackoverflow is your best friend ..
I would suggest spending time, rather than your money..