$1000 to make my prius quiet

Replace the bearings. That's what I did on mine after there was a loud humming noise that grew louder as I accelerated. If you're driving in a salty area like New England like I was, I suggest just going to a junkyard and getting a whole new knuckle assembly. Trying to push the bearings out the first side of a totally corroded spindle was a BEAR. Plus, save yourself about $240 from getting a new bearing, and easy to see if that was the problem.