What you mean is not a cost to acquire the data but a sum paid by the highest bidder in auction to acquire Navteq corporation.
Value of maps is much less or to say in other words, has been overvalued.
But, on the other hand, TomTom also paid a lot of money to acquire TeleAtlas.

Buy want counts is not maps but market share in vector maps world.

I am sure, you are aware, maps are not build by cars travelling each new build road in the world.
Road tree system in electronic form is available for purchase from Highways authority in each specific country so to have your maps updated maps developer doesn't have to visit each new built road and enter it separately into navigation maps repository.
He buys a ready made product in electronic from from roads administration.

Another way is to have satellite nimages converted into vector maps
and have road extracted from satellite images.
I worked for CT /USG tomography projects and intelligent image processing of medical images shows you how to have roads only extracted from satellite images.

Finally, you can get and use maps for free visiting Google maps/ Google Earth, Yahoo maps, MS maps web servers.
You can get free maps from open source maps projects like OpenStreet and others.

So maps have some value but to use them you don't need to pay much.
Some car navigation systems in US start from as low as $100.
(road maps + routing + voice commands + hardware).

Maemo Mapper is based on maps accessed through Internet (Google, Yahoo, OpenStreet and others) and using it you pay nothing.

So maps business, navigation business sometimes generates no profit at all as there are hundreds of gps car navigation devices and systems on the market nowadays.

Darius

Darius