Considering your budget, if you really want a diesel-powered car, you can go for the Hyundai Accent CRDi. Yun nga lang, manual ang transmission.

If you're looking for a car that doesn't cost a lot in terms of maintenance, you can try the Suzuki Swift A/T (hindi nga lang sedan). A number of owners claim fuel efficiency on their Swifts, and the best part is you get free maintenance from Suzuki for the first two years.