If doing it yourself, beware of firebreaks in the wall. If you encounter one you are toast unless you have a 6 foot long drill bit. The installers have a few different tools that help out and I chose to just pay the bucks and let them do it. Damn glad I did because it wasn't easy.
2 guys @75 per hour each x 6 hours but in the end it was worth it to me. I got to be the 'manager' and say 'I want this wire to that wall plate, a new CAT5 to that room and the equipment closet, blah, blah, blah.' They listened to me and only caused very minimal damage around one existing wall plate.