I'm looking to place a fair value on my M&P15. It was an optics ready model, and I have replaced the stock with a fixed stock, grip with Houge, handguard with a FF tube, front sight is a YHM flip up gas block sight, rear sight is a no name flip up, and a phantom flash hider.

A new optics ready carbine at my LGS is $899 without the options. Mine has been used, but nothing extreme (less than 700rnds of 5.56).

What would be a fair value to ask for mine?

What kind of stock? What kind of FF hand guard? I've seen the OR going for $799 recently.

You might want to part it out. You prolly won't get much for it in its current state unless someone just happens to be looking for that exact config with the same brand of parts. $750 maybe?