There are different models, standard features, and calibers of the M&P, which would affect price. For a used weapon, the condition would also be a major factor.
The M&P comes in 9mm, .40, .45, and .22. There are also different calibers in the various M&P series, such as Bodyguard and Shield.
New retail values will be somewhat consistent.
Examples:
A new Smith & Wesson M&P SHIELD 9mm with no thumb safety would retail for around $450.
A new PC Ported M&P 9 Shield with Tritium Night Sights would retail for around $600.
A Smith and Wesson M&P 40 is a .40 caliber hand gun.
10-1000 usd
Yes
100-350 or so
I believe that would all depend on where you traded it, and for what.
300-600 usd
Right now the M&P
Yes it does. The M&P is a fine weapon.
Military and Police
No
You can request a manual from the S&W website
10-500 usd