I picked up a 2003 Expedition last year for a low price and have put about $2200 in to new tires and front end rebuild. I just love driving that thing! Next up, new upholstery.
What engine? Make sure to ask Chat about the common issues with that model (there always are with Fords since 1996 or so), so you don't have to find out afterwards. I say this as a victim of an Exploder (2010, tranny) and Expedition (2012, timing belt).