We booked our flights in May for the trip in November. Mumbai Chennai return fare was INR 2500. We booked our cab through Make my Trip. We took an SUV for 6 people plus driver and paid INR 9000 for a round trip. We hired a cab because we wanted to stop by at a lot of places en-route Pondicherry. Bus options ( ₹200 per person from Chennai to Pondicherry) are also available.