Thanks, @SholaIB
There are tickets of about 3000 and 2000 INR for the pavilions but I enjoyed the race from the comforts of the houseboat where I was vacationing on that day.
Moreover, the Kerala backwaters where the race is conducted is heavily populated along the banks, so people enjoy from the streets and from the roof-tops of their houses, but I think the culmination of the race is the finishing point which can be witnessed only from the stands, so buying a ticket seems to the only option if one wants to be part of the excitement.
~Greetings from New Delhi!