Don't pay them $500 to clean your :q:q:q:qing throttle body. You know what they're gonna do? They're gonna pick up a can of throttle body cleaner, and spray it in there. Takes all of 5 minutes to remove the intake hose, spray in there and put it back together. I could see maybe paying for a trans flush, but honestly a drain and refill will do just as well.
You can do a better cleaning at home in your driveway for about $20. Go get a can of... you guessed it, throttle body cleaner from your local parts store, and a throttle body gasket from the dealer. Grab yourself an old rag or toothbrush and you're read to go.
There's 4 bolts that hold the throttle body on, remove the intake hose, disconnect any wire harness plugs, and pop the throttle cable off and you can remove it. Clean inside as best you can with the cleaner and tooth brush, scrape the gasket surface clean with a plastic scraper and re- install. Then if you want to go the extra mile. Seafoam it.