I was looking at vehicles the other day here and chatted to a few people. To be honest I wouldn't trust buying second hand.
By the feedback I got there are some good deals to be had when buying new, I looked at an Isuzu suv and a Misubushi Fortunate, the Mitsubushi came in at about 15m php, the Isuzu about 12 I think. Both should be available over a 3 or 4 year deal, or maybe a discount for cash
I'm sure someone with more experience will give much better advise