Gee, I'd give you $250 for it right now.
But honestly, the value of the A-Bolt .22's keeps increasing since Browning stopped making them. I've seen posts from a few lucky people who got a deal on them for $350 or so, but they often go for up to $450 or higher, depending on the grade and condition, whether it has sights or not, if it's in the box, things like that.
There is a "Blue Book Of Gun Values" available, but you can seldom get what they say a gun is worth. Best thing to do if you're not sure of the value of a gun is to watch the gun auction sites (just do a search for "Gun Auction") and see what they're going for on them. I have a friend who is trying to decide if he wants to sell his A-Bolt .22 so I've looked at them for him. The last couple I saw up for auction were starting at $450 and $500, but I don't know if they sold or for how much.
Definately don't take less than $350 for it, unless you want to sell it to me.
Dan