IMHO, that's an awful price....
I leased one last fall...
XLT Super
5.4L FFV
4x4
Tow Pkg w/brake controller
Fogs
alloys
running boards
3.73 rearend, etc....
$381/month...nothing down.
You're proabably looking at $450 for your Lariat and other crap, if you really need all that. Doing without your Lariat pkg will drop you down a good $40-50/mo.
Everyone's entitled to their own opinion, but....
Leasing, in my situation, is cheaper than buying it out. I've had this truck since September, I have 4,100 miles on it. I have already agreed to purchase the truck at the end of the lease for $16,700. At that point in time, I'll have a $37,000 truck that is three years old with MAYBE 15,000 miles on it. If you crunch your numbers, leasing then buying can be cheaper. In my case, I'll be saving $2,000-2,500 leasing over buying.
We also seem to trade up every 2 years or so. Leasing is a MUCH more viable option in this case, let's face it, these F150's don't hold enough residual to purchase it, then trade it away.
Keep working on em, they'll nearly give you that truck. I got mine for $500 over invoice. and got an extra $1500 over book for my trade.