When is the best time and the cheapest time to travel to Europe?

Beginning of September

Generally winter, but of course it depends on where you go. Europe is not a country, but a continent, and in some places (notably ski areas) winter is obviously high season. Obviously, Christmas and New Year are always very busy times and prices are correspondingly higher. Asking ´what is the best time´ to travel to Europe is rather pointless unless you give details as to what your interests are. Do you want to swim in the Mediterranean? Then go between June and October. Do you want to experience relatively uncrowded cities? Then go to Paris in August, or London in February. Do you want to ski? Then go between November and May, depending on the ski resort. Do you want to see the processions in Seville? Then go in Easter week.....

Stowaway in summer.

Winter....September - November