I am about to buy a NEW TRUCK need help!

I found a 2007 demo ford f-150 crewcab 4.6v8 crome pack. gray 2 tone w/ 8000miles on it.
new!!! sticker price 31000 They went down to 21900 I told them I thought they could do better but they said they can not. I am looking into finaces and will know more tomarrow!!
I will not take anything over 400 a month. I will walk!!! What do yall think!!!!