In reply to Paul R:
I will assume you are driving from Calais (or a nearby Channel port)!
In which case France (on this route), Belgium, Netherlands and Germany are toll free. There is a motorway pass charge in Austria and a toll for the Brenner pass, these can be avoided by taking the Gruner Tauern pass into Italy.
This route (Brussels ring, Aachen, Koln, Munich) is the easiest drive, the Liege road is not as good. I have tried them all!