I am on vacation in Texas and stopped at a Flying J for fuel.I always like to stop there with RV as there is plenty of space to get around, well anyway i traded my 09 F250 for a new 2011, 2 days before i left and now this one also needs DEF, as my BT. Well DEF goes for $2.38 a gallon at the pump here.Just stick the DEF nozzle in tank and it clicks when full just like a fuel pump. Convenient and cheap, if you do live near a Flying J,most are called Pilot now i think.