Is $1,200 to mud and paint 3 walls a fair price?

I got this quote for mudding and painting three walls where I hung the drywall myself. I've mudded before and it took me weeks of sanding, so I'm willing to pay someone to do it. I initially got an $1800 quote but talked them down to $1200. The drywall was put up because we have a new puppy that was eating the insulation out of the walls.