IIT Preparation

Hi Suraj,
FITJEE - Patna is the best option and its fee is for Rs.2 lakhs for 2 year program. If you want less fee, then you can opt Mentors Eduserv, as the fee is Rs.1 lakh.

There are success and failure stories of JEE with or without external support. The choice of going for self-preparations or coaching for JEE depends upon your personality, intelligence level and budget. If you are self-determined student with high IQ, who is focused and capable of achieving targets based on self-assessment and hard work, then you can opt for self-preparation.
You can also join mock test series with coaching institutes along with self-studies, so that you can assess yourself with others and take corrective action to overcome your weakness.

No, as the pattern is changed, but formulas and concept is same.

You can check the below mentioned link:
https://www.shiksha.com/b-tech/articles/best-books-for-jee-main-2020-preparation-blogId-19529

Hello Aman,
If you are clear about your career that you want to be in IIT then go for it. You can drop and start preparation but don't spoil one if it's not serious for you.

There are some coaching that offer free IIT preparation by conducting some exam for their coaching institutes. By giving those exams, you can get admission in those institute that will lead you to free coaching.
Examples are: Super 30, Anand Kumar Institute, etc.

You can refer to the following textbooks:
1. Cengage for mathematics.
2. Dr. OP Tandon for chemistry.

IIT preparations will help you to crack NDA provided you are able to put additional effort on general awareness.

FIIT and Vidyamandir are the best coaching centers for the same.