Few airlines like Spicejet have come up with a lower fare option called hand baggage fare for passengers who are travelling without any check-in baggage. These fares are generally around 200 to 500 cheaper than regular domestc airfares in India.
These customers may carry cabin/hand baggage upto 7kg. For any baggage other than cabin baggage allowance airline will impose charges on that ticket.
Generally if a flyer has booked a ticket under hand baggage fare but has checkin baggage as well during travel airlines generally offer to allow to upgrade to regular fare with nominal baggage charges of around 500 per person for 15kg checkin baggage.
Prices mentioned are approx figures. To confirm the same please contact airlines directly for updated information.