depends on how bad you want it and what you are willing to pay to get it.
What is the value of the firearm, out of the box and in the cabinets it is not new, fired 1x or 20x it is used but not abused.
Based on what I have seen here you could expect to see the as new price without the taxes, to saving 150 -200 bucks depending on how bad the seller wants to move the gun. Typically if the firearms is a brand name and and in good condition then you will likely pay more than if it is a sporterized milsurp or clone of something.