Hi OP, As you say this is your family's first holiday in France, I am going to assume that you will not be eating out much, if at all. So, your first stop after checking in at the campsite, will be the nearest Carrefour/Supermarche/Geant etc. You will find many items cheaper than here, beer, wine in particular. Meat and fish can be pricey in those supermarkets. If your campsite provide a barbecue, you can buy steakburgers and such quite cheaply. On site, there will be a takeaway and maybe a restaurant. These will be pricier than the town but ok for occasional use. Drink in the bar onsite, especially soft drinks, will seem pricey so best to avoid buying too much of that. Most of the campsite activities will be free. There are loads of McDonalds' in France, useful at times for eating on the go and wifi! Based on this and my own trips to France, I would say you can easily do the holiday for no more than €100 per day and that is allowing a generous sum, including some for fuel. So, bring or, better still, have access to at least €1,000. Best not to have that much cash in your tent/mobile home. Campsites are very secure but you never know. Bring €500 in cash with access to at least the same on your ATM/CC. Bon Vacances!