February last year (2011) I hired a van from Avis near Zürich airport (last tram stop before airport in fact) to move all my stuff home from Switzerland.
I got a 20% discount because the company I was working for had an arrangement *but* they seem to give out discounts all over the place (I think maybe if you fly with Swiss, have a Mobility card etc...)
I *think* it worked out to about 300 GBP (just for the van hire). I hired the van for 4 days which included 2000km limit and came in pretty much on the nose.
They knew I was driving to UK so that was all included. Can't remember cost of diesel. Tolls worked out to quite a bit *but* since then any time I've driven I've gone via a non-toll route i.e. cut through a corner of Luxembourg where fuel is v. cheap (comparatively) -> Belgium -> France -> Dunkerque ferry. This might be marginally longer as a route but has a few other advantages over the French toll road route e.g. more of the motorway is lit.
Of course when I landed another Swiss contract month and a half later I had to get all my stuff over again, but that's another story....