I suggest Toyota Corolla or Mazda 323, should get a good one for under 15000.
IMO avoid Opel/Ford/BMW/Merc, etc. Stick to Japanese and avoid Hondas and Mitsubishis that may have been used by boy racers....obviously MPVs are probably okay..Make sure the a/c works!
There's a few small time dealers who sell on here and particularly asiaexpat, they are usually pretty good as they work on quick turnover rather than cleaning up, clocking, etc.
It's worth watching the classifieds regularly as some amazing bargains come up from time to time when expats leave things too late...
One more question for the folks who know about the tax - I think it's first registration tax, would the valuation be based on the receipt from the country of origin or a local valuation?