I have a similar problem but only when it's cold. I checked everything I could find, nothing seems wrong but on a cold (below freezing) morning when I fill up I can't get much in without it blowing fuel back out. I've found that if I fill on my way home, after having driven it the whole commute (about 40 miles), it fills just fine. I've taken it to the local dealership and there was no problem so they said 'bring it back when it happens again.' Since the dealership is about 45 miles away it's always warm enough to not be a problem. It has to be some kind of vent somewhere but I can't find it.

Another thing, I get the faint smell of gasoline sometimes in the morning also - only those cold mornings though.

I know what you mean about the fees for changing fluids, I took mine in to have the vacuum hubs fixed and they said I needed to have the fluid changed in all the gear boxes - for $150 - that didn't include the charges for changing the engine oil. I told them I'd do it myself instead. It must have pissed them off because while it was in they changed out both front C/V shafts, something I never asked for or even asked them to check. I think someone screwed up and they were trying to recover some expenses. The repairs were all under warranty so I can't complain too much.