Applicable from 8 July 2016, It has been made mandatory for Karnataka-registered tourist vehicles with all-India permit to pay the entry tax for the whole year. This is irrespective of the number of trips made to Kerala that year.
Following are the rates (not verified) -
Taxi — 4+1 seater: Rs. 2,000 per year
Taxi — 6+1 seater: Rs. 6,500 per year
Taxi — 7+1 seater: Rs. 25,000 for 3 months
Maxi-cab — 12+1 seater: Rs. 1.68 lakh + cess per year
35-seater bus: Rs. 4.9 lakh + cess per year
45-seater bus: Rs. 6.3 lakh + cess per year
Source: http://www.thehindu.com/news/cities/bangalore/Trip-to-God%E2%80%99s-own-country-gets-dearer/article14510606.ece