France
Have just returned from a two-week family holiday in France having exchanged my home with family in the Loire Valley. Would recommend this type of "home stay" for complete experience of different country and culture.
There are some huge, very well equipped, teeming and expensive campsites in the Loire Valley. There are also many small and cheap campsites run by the municipality - some in the most delightful places (one at Nazelles Negron near Amboise runs wine tastings and has a pizza van some evenings). We paid around 7-8 euros a night for two of us and a tent, and enjoyed a shady riverbank. There's also one we didn't stay on right next to the chateau at Chenonceau.