So far the cheapest I have found is grabagun.com at $319. Anyone know of a better deal? I will likely be ordering it tomorrow.

It's $299 a couple places.  Hopefully the forum's ad crap doesn't break the link.
Wikiarms

Buy a used one locally or on the EE...it will probably be cheaper.

And we have a dozen or so vendors for new firearms.

And you have the internet, and the large distributors like davidson's, grab a gun, etc, etc.

I mean if you are so concerned over paying the extra $20, just call them and ask them if they will throw in a box or 2 of some ammo...or a extra mag, or knock off 5% and free shipping, etc.

The only thing stopping you from getting a deal seems to be you.


_

Why not go with a standard lower, and a Chiappa M4-22 upper?  Just curious what the M&P has over going that route...

Got mine from Grabagun for a good price.   They have inexpensive magazines too.