how much should damper on top of chimney (near roof) cost? We are being quoted $475 including installation MD?

need help fast. we are trying to address smokey smell in house after fire goes out

Usually the damper is down near the fireplace. It opens or closes when you need it. The price doesn't seem out of line. I don't see how that would affect smoke smell in your house though. Unless your are not opening it far enough for a fire.
$475
Dampers are not located at the top of a chimney, that's where the screen is installed to keep hot ash and embers from floating out of the fireplace. Try getting 2-3 more bids, $475 sounds kinda steep for a chimney screen...I had one installed for only $80. To keep your fireplace from smoking up your house, always crack a door or window nearby to keep a sufficient draw of air going. Fire needs air to properly draw the smoke up and out of the chimney. Keep your damper open until all embers are extinguished...then you can close it to keep warm air from escaping through the chimney flue.
That's a little high. But the price of metals has gone up sky high. Stainless steel is out of site for a top damper. I know copper has gone up 400% in 2 years. Its probably not that bad of a price.