We bought a pre-owned Isuzu pick-up truck about a month ago and it was quite tedious hopping from one showroom to another. I don't know if there are sites that offer information on used car sales and car buying tips here in the Philippines but for those who live in the United States, there's Smartcarguide.
Smartcarguide offers comprehensive information on new and used cars for sale. If you are looking for used cars, for example, you can easily perform a search by brand or by location. Each search result is comprehensive in itself. You'll find information on car features and model, selling price, location, and mileage. The site is very easy to use and you even have the option to refine search results.
Also offering information on auto insurance and financing, Smartcarguide is truly a one-stop resource for those who intend to shop for cars online.