ok from that i understood that you want to do something like this car has in your car. but i really odnt know what you mean by "putting this in my." hahah and i just now saw your sig "those who understand nothing know nothing" . i guess im just a big ol' dummy then. 
Well, that would be a pretty ambitious undertaking for a begginer I think. Custom door panels and a custom radio bezel?
The door panels would not be as hard as you think. Build the form the speakers will go in out of MDF rings and dowels. Then fiberglass it. Sand, sand and sand some more. Prime and paint.
The radio bezel? Well, measure out the screen you want to put in. Make up a template and lay it out on the bezel. Also, it would be best to build an MDF surround for the screen. It is easier to mount. Again with the fiberglass and sanding. Then primer, sand, paint and enjoy.
It all sounds much easier than it truly is though. That is why most people pay to have it doen... and pay so much. As for cost, the material is not too bad. Check out the Select Products website. They sell everything you would need to do something like that. Well, everything but the AV stuff.
Cheap is a relative term! Of course at the fairgrounds near here there is an car audio blow out sale. I can pick everyone up some subs for only $5... CD players for $9.99! I am sure you would all pay me back when you go the cash... right?