Moving to Sri Lanka

Hi, to live in Sri Lanka, say, just on the outskirts of Colombia, including food , rent of a small and modest house or apartment , medical insurance and utilities, how much would one need per month? Thank you

Welcome to the forum  :)

For living costs try www.numbeo.com 
Check the housing section top of this page for housing costs.
Cost of medical insurance will differ depending on what sort of coverage you require.
A Google search will help for additional information.