In response to the OP, I can't really say what the Model 12 should sell for, but I don't think I would let it go cheap.
I always read threads about the 16 gauge with great interest. There always seems to be comments to the effect "Not much of a market for them, giveaway prices, ..." When I was looking for one on the used gun market, that certainly wasn't my experience.
Originally I thought I would get a Browning Sweet 16, but quickly discovered they were priced very high. Other makes/models were all priced at least as high as their 12 gauge counterparts, at least from what I was able to glean from the internet.
So I just started looking local. Nobody had any, except for one shop that had exactly one Browning Pump Shotgun, made in Japan by Mikoru. They wouldn't budge on the price, so I gave in.
Maybe I don't have the dedication or patience that some others here have, but I sure couldn't find any low-priced ones. I imagine if you go to sell it at a gun shop you will hear that "dime a dozen" stuff.