Run each flight search twice, once on Regular and once on the special fare you qualify for, and add the airline's extra-baggage charge to the Regular total before you choose.
On the MakeMyTrip flight search, you pick a fare type before you search: Regular, Student, Senior Citizen, Armed Forces or Doctors and Nurses. The results follow the fare type you picked, so a search left on Regular only shows regular fares. Senior Citizen fares are only for travellers above 60.
The Student fare can come as a lower price, extra check-in baggage, or both, depending on the airline. This means the saving is sometimes in the bag allowance, not the ticket price. If you fly with a heavy bag, a Student fare with a higher ticket price can still cost less than a Regular fare plus paid extra baggage.
These fares come with conditions that are checked at the airport. Students must be above 12 and must carry a valid student ID card, plus a student visa where one applies, or the airline can deny boarding or charge for the extra baggage. The Armed Forces fare covers serving and retired armed forces and paramilitary personnel, their recognised dependants such as spouses and children, and war widows, and you must show a valid ID or dependant card at the airport or boarding might be denied.