I use a standard fridge freezer with the following thermostat which I bought from e-bay for £8.96.
That's 852 Rupee at today's exchange rate.
I actually have 2 of them and they can maintain a specific temperature within 0.1 degree.
I have found them to be excellent.
90~250V 10A Digital Temperature Controller Thermocouple -50~110℃ with Sensor UK
E-Bay item number is 310910389174. Just put that in the search and it should bring it up.
It comes from UK but it was post free to Greece, not sure about to India.