I had to replace the passenger side front fender. Online is the cheapest you are going to find it. I got mine from xterrastore.com (Marlboro). Cost me $171 (give or take some change).
It comes to you in primer black.
I'm not sure about having someone else paint it and you installing it - I had it all done at the same place.
They may need your truck for a little while, just so they can match the paint.