I'd try to buy from an expat if you know anyone selling a vehicle. We tend to look after them better and get them serviced often with quality parts and oil .... Locals tend to leave everything until it breaks

Go for T Sure (Toyota certified pre-owned) or try bank pre-owned cars. Those are the most trustworthy when it comes to paperwork.

Get a jeepney 😉

Yes, use FB Marketplace. The key is going to see the vehicle — look at it, touch it, drive it. Have a mechanic look it over. I bought a used Toyota and it's been a great car. They're out there. Check dealerships too for returned cars on their lot. Financing here is a joke. The banks get poor locals into crazy loans with extremely high interest rates. Local buyers can't keep up with the monthly payments — they're brutal. After a few months of missed payments or struggling, they realize they can't keep the car. Some get repo'd, others get returned. Those dealerships have those cars, and those are good ones to look for.

When I retire in the Philippines, I won't buy a car. I'd rather commute for everyday errands and rent a car with a driver now and then.