Don't ever trade a vehicle. All a dealer will ever give you is wholsale. Put it in the auto trader or ebay and see how much the current market will bring. You never know how much your getting in a trade because they hide it in the price of the new vehicle.
And extended warrenties are only as good as the dealership doing the work so bying used is not allways the answer. Get your loan before you go to the dealership, know the wholesale, retail, and dealer cost before you deal. Don't let them talk payments, tell them you wan't the price ou the door.
My 04 reg. cab 2wd 4.7 auto with manual locks, and windows had a MSRP of 23K in April of 04.
I payed 16.2K. It's an SXT modle with air, cd, cruise chrome wheels, drop in liner, rear slider and bug guard. I still think I payed about 2K too much, but the market was a little stronger then.