Blue $750.00-$900.00 Nickel + $50.00-$100.00 4" seems to fetch a little more as well.Not many around to choose from get it for what you can if it is nice.
Got a blue 6" 57-1 in excellent condition last November from a local pawn shop at $525. They seem to bring a higher price than similar revolvers in .357 & .44. I guess they are of a different caliber!