Keef -- I'm not sure you're right about avoiding IFR charges by making a VFR departure (assuming your aircraft is heavy enough to incur IFR charges). My understanding is that IFR charges are incurrred if ANY part of the flight is IFR.
Of course, if nobody knows you're IFR, then you won't be charged.
But the whole point is that you go IFR either because your weather is worse than the VFR minima or because you chose it for safety/convenience. In either case you chose so should be prepared to pay (without opening the avgas duty etc cans of worms or the 'but I got no service' argument ;-)) ).
AA.