I replaced the plugs myself @ 60K miles, was a pain in the a$$ for the back 2 but it can be done by yourself. Funny thing was my Dodge dealer told me the same thing about the brake booster - then again this "particular" dealer is horrible and they will do anything to make a buck.
*When I was deployed to Iraq a few years ago they told my wife they would replace her head light bulb for $83!! LMAO! What they didn't know was Mama is quite compitant herself with some basic automotive skills - she told the service manager his mechs need to quit smoking dope out on the shop floor. ha ha $83 for a head light seriously?