I actually get Motorcarft at Wal-Mart...I can't get Rotellia because I made promise a couple years ago that is long story lol, anyway if you have trouble finding Rotellia oil cheap I would recommend TSC, Orscheln Farm and Home Store, Boomgars(sp), or some kind of farming supply store or your local International Truck Dealer...they have a freaking giant supply/display here in Lincoln.