Replace the water pump too while you're at it.
No way it should cost more than five hundred. Find someone else to do the work.
My regular mechanic doesn’t do Subarus and everywhere else around here wants obscene amounts of money to do it.
Might have to go down the street to the redneck garage and offer them cash. I think they’re reasonably competent.
Any reputable place should sugest the above, since the labor will be the biggest part of that bill and if you only do a partial, you will soon be doing the other side..
Depending on the shape of the vehicle and the mileage you got before it toasted, figure with redone head gaskets it will get another however many thou miles. (Head gaskets fails are notorious on Subaru's, especially the 1998-2006(?) vintage, usually at around 125k miles give or take. Don't know if they have 'fixed' it in the latest models or not.)
Anyway, having it done right by someone you have to pay to do it (as opposed to doing it your self) should run you more in the vicinity of $1600 unless the labor rate down in those southern parts of Joisey is a lot more expensive than up in the lumpy part of the state where I took mine (in the shadow of the Highpoint monument).
I chose to fix the head gaskets on my '98 because the body and everything else was in good shape, and if I get a second 150k out of it I come out ahead.
Your mileage and comfort zone may vary.. ;-)