After getting 99 percentile in CAT and for getting admission in IIM. Will I' ve to pay fee for study MBA or its free off.

No, the application fee for Amrita CAT can only be paid online. There is no provision of offline payment. 

CAT exam conducted only once a year in the month of November. It is conducted in three shifts on a single day.

CAT exam is conducted in computer based test mode. Candidates have to visit a designated test centre to give the exam on a computer system. They have to login their answers with the help of computer mouse.

Maximum marks in CAT is 204. There are 68 questions each carrying 3 marks. VARC is of 72 marks and DILR and Quants are of 66 marks each.

CAT exam is of 120 minutes. Each section is of 40 minutes. PwD candidates get extra time of 53 minutes and 20 seconds per section.