The answer to your question depends on how committed you are to the car you buy.
If you are not a committed car owner and hope to pump petrol in one end expect miles to come out the other, buy a 0 mileage jap car thats very popular right now with a decent warranty, from agents or a reputed importer. And sell it off before it gives trouble (e.g. wagon-r, aqua, fit, axio, vezel) If you are ready to commit i.e. don't mind putting in a bit of time and effort to look for parts or sit on a garage bench, or simply put, if you got good contacts in the local car scene, first of all congratulations on being a human being. You've just opened up the pandora's box of local cars. Now you can buy the sort of car that makes the typical sri lankan motorist run the other way. you know the type who start a conversation asking "meka thel keeyak karanawada?" The cars range from performance or left field jap cars to the less obvious euros and classics. Maybe the odd american or korean here and there. This sort of car will most of the time hold its value if not appreciate, it'll definitely put a smile on your face everytime you take it out, all in exchange for a little bit of tlc.