"But I'm not seeing gun dealers do this. It's private, individual sales primarily."
I know one successful gun store over in the Valley that has listed 2 prices on their hang tags for the past 15 years or so. They list the cash price and the trade price - which is usually $100 more on your typical $1000 to $3000 shotgun by Guerini, Browning or Beretta.
They do the same on their handguns, but being a cash customer I don't recall the price spread.
It takes cash to run a business and a bunch of extra guns sitting on the shelf for some unknown period of days or weeks won't pay the bills this week.
I suppose the short version is that there's a discount for cash buyers.