The cost depends upon the make/brand u want to get installed.
a normal sony dvd in dash player will cost u around 16000 RS. And changer around 25000 to 30000, u can buy it from any sony dealership... Easy aann...
for pioneer or kenwoods the cost would be even higher.. As they come with in dash screen and other features which sony doesnt have.
as i have 2 dvd players installed in my car my experience is that sony only makes crap for cars. Pioneers are D best.
china made dvd players on d other side are soo cheap that u can change them every year if they malfunction.
4000 to 8000 for dvd player with usb ports and 12000 for with in dash LCD
hope this helps u in finalyzing......