im looking to sell my remington 870 slug gun its in mint condition and has 8 slugs through it. It has the fully rifiled barrel. I was wondering what would a fair asking price would be

I see em all the time in pawnshops in the 250-300 range.it may bring a little more in a shotgun only hunting area.

870...of what configuration? Blued? Camo? Wood? Synthetic? Rifle sights? Scope mount? Magnum or super magnum? Who is the barrel maker?

Those could be selling points, even though they will all be in a similar ballpark for price, if it's an express. Keep 'em in mind.