It seems that prices have a least stablized in the last number of months. I bought two stainless 7.5" ROA's NIB in the early part of 2009.
The first one, an adjustable, came in the original cardboard box, with papers, and the original purchase receipt ($213.45 on 11/11/83). I wish I could say I got it for that price but I gave $498. Adjusted for inflation and the devalued dollar I may have just about got it for the same price. The second one I bought, with fixed sights, came in the plastic box sealed from the factory. I gave $495 for it.
In my case I was willing to pay the extra $100 for a virgin ROA versus one not knowing how well the previous owner cared for it. From my observations the used ones are going for $325 to $400 blued. Stainless, another $50 higher. NIB ones seem to be starting at around $500.