Not being rude, just honest...it applies to me as well, as I've got one sitting only one room away from where I'm typing.
$300 is tops, only if someone is looking for a laser grip. For me, without the laser, I'd pause a bit before handing over $250 for a gun to leave in the cabin maybe.
What I'd do instead is, keep it and maybe buy a .357sig barrel for it - that's all you need for a gun that shoots a boutique but very high performing round. Use the .40 tube to practice with and carry it with .357sig.
You won't get a fair bit of coin for it, so you might as well enjoy it.
Or make it the gun you store with 1000 rounds of ammo, sealed in dry vapor bags in a watertight container... about six feet underground, somewhere that you'll remember where you buried it again if needed.