Nav with backup camera...
 

About how much would it cost to have this installed in a 40th from the US?

Besides the fact that this belongs in the AV section, you're asking a question that could never be answered in such a simple form. Do you mean stock or aftermarket? What brand/model/features?

You'll find (if you searched the site) that installing the factory nav would cost 2-3 times the price of the package due to the fact that it requires so much dissasembly and replacement of much of the car's wiring harness.

Aftermarket depends on what you buy and who installs it, could be mid hundreds, could be several thousands.

Install only can be done at home with basic hand tools and a little bit of research online.

Be more specific, and I can give you a more specific answer :)