Depending on your state and local laws, you may be able to advertise it in the newspaper and sell it to an individual. You may be able to take it to a gun show and sell it to a dealer. You may be able to consign it to a gun shop or pawn it. That shotgun is reasonably valuable, so you will want to get an idea of its value and what you will accept for it before you try and sell it. Go to auctionarms.com and see if there are any like it up for auction and what the prices are.
200-1200 usd
500 uSD
500 or so
In the neighborhood of 550 dollars.
100-1000 USD
500 USD or so
100-300 usd
You will have to call Browning.
I bought mine in 2005 with the zippered pouch and the manual for $365. Condition was 96%, function perfect.
100-500 USD or so
in poor, nonworking condition its worth $50-$100 , in poor condition but still working properly its worth $150-$200 , in fair condition its worth $250-$350 , and in mint perfect condition its worth $400-$500 .
A Browning Ducks Unlimited 12G in perfect condition is worth $1100-1400 That's what the last six got sold for. It's a truly beautiful shotgun. The rusty ones at pawn shops sell for $500+.