I just mounted my 60" ST50 on the wall 2 weekends ago and it took me about 2 hours to get it all done. This included cutting 4 holes in the wall for 4 wall plates (only 2 were to run the wires from behind the TV to the receiver). Granted you need a few tools to do all of this, but $250 for it seems pretty ridiculous after doing it myself. But then again, I like to do things myself and learn as I go along.
FWIW this is my first home of 2 months, and I had done NOTHING of this nature prior to this. And this was after I ran Cat5e and coax to 5 rooms of my house through the wall, again, all myself having 0 prior experience.