Edmunds is a very good site to use. If you choose the options of the specific vehicle then it will tell you an approximate invoice price.
I just built a 2012 F-150 XLT 4X4 with options that would reach a $41k MSRP. Here's the link: LINK
Click the button "Get true market value pricing" and it will give you an approximate invoice price. Very accurate. You could get it for around invoice price minus rebates. They are currently:
in Total Savings
Ford Credit Bonus Cash
For 2012 Ford F-150
SuperCrew 5.0L V8
w/ XLT Convenience, Chrome & Tow
I think it is $1000 less on the rebates if only a V6 engine (not 100% positive). Also, I do not believe Edmunds rebate information is correct. I pulled the rebate info off FordVehicles site.
Edit: $500 less on rebate for a non-5.0L V8. Just found it.
This post was edited on 6/21 at 9:36 am