In the Car DVD Players Wiki page, you will learn how to choose a suitable car DVD player and things to consider when choosing a suitable system for you. For example, you may need to consider extra features such as GPS Navigation System and ability to play iPod songs.
There are different types of Car DVD Players which suit different budgets and usages. For example, you may consider a Ceiling Mount DVD Players if you have a lot of budget, or you may get an In-Dash Receivers if you want an economical one.
If you bought an high-end system, you may also consider to read about their Anti-theft system page and get away from thieves.
ShopWiki has provide us a very detail guide on buying and you may easily search for any product using their search engine.