In perspective: taxi from NRT to Tokyo can cost around 30kJPY, aka 250USD. Obviously EK J/F cars can't be just normal taxis, so think 35k,40k,50k yen. (410USD).

Alternatively you can take a helicopter transfer - which takes 20 minutes and is 2500USD. Car included for last leg of your journey from the helipad.

HND is quite close to central Tokyo - therefore, more reasonable for taxis and car services.