You can go to
http://www.onemotoring.com.sg/main/default.asp for information on the PARF & stuffs.
I think u need to go to classified ads and then try to find a price that is closest to your budget. If you are budget conscious, just try to remember that car is to bring you from point A to point B and reliable.
The above websites also give tips on how to buy a car and what to look out for.