Hello,
You can pick any of the specialisations for Masters in mechanical engineering-
Automobiles
Material science
Thermal engineering
CAD/CAE
Hydraulics
Mechatronics
Nano technology etc
First choose a field of specialisation, and then go through the colleges that offer the course you are interested in. The better the gate score, the better the college is going to be. If you want admission in top colleges in IITs/NITs etc., you should have an excellent score. The fee and all is comletely dependent on what college and what branch you are going to take. Hope you understand.
Good Luck!

Dear Reader,

There are n number of colleges available for pursuing masters in india including government colleges like IIT, NIT, IIIT and also a lot of reputed private colleges which provides admission on the basis of GATE score.

Kindly visit the link mentioned below to know the cut off for various colleges and other details you require.

https://engineering.careers360.com/articles/gate-counselling

https://engineering.careers360.com/articles/gate-cutoff-for-me