Well, that really depends the way of traveling. I am going on a solo trip to Karnataka and Kerala in June and my estimated budget is approx Rs. 300 per day. But I also know a guy who travelled across India for 6 months in Rs. 2500.. I plan to do hitchhiking, sleeping in my own tent and eat at local food outlets to save on money so that I can travel longer. Also do consider Couchsurfing and Volunteering for a diverse experience.
It depends on your choice of hotels & for how many days you want to stay.
There are many good places to visit in Kerala & you can plan your stay accordingly.
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