whats a fair asking price for a used S&W M&P 15/22

AR/M4 AR Pistols & Pistol Caliber ARs
1

i have a lightly used M&P 15/22 about 500 rounds through it…
it has a threaded bbl with a A2 flash hider & Magpul flip up sights
with 4 mags 2 25 round and 2 10 round…

2

I’d say 350.00 to 400