The only reason that the Rangers are so cheap s to help raise Fords Fleet mileage average. Ford sells so many F150s and Other trucks/SUVS that they need to keep their fleet mileage at a level low enough as to not warrant fines.
This was my understanding anyway. 198 a month is a pretty good deal, however later on in the spring you might see some even better deals, (I've seen 150 and even 99 a month, with a nice amount of $ down anway)