You'll have at least four expense items in Joan-les-Pins: airfare, lodging, transportation, and food. Calculate for yourself the price of a vacation in Joan-les-Pins:
Air tickets to Juan-les-Pins (Nice airport) with a transfer will cost 200-270 EUR round trip.
The average cost of accommodation in hotels in Juan-les-Pins of 3 and 4 star categories is 60-90 EUR, in 5 star hotels - 120-400 EUR.
Renting a car will cost from 50-70 EUR per day. But it is cheaper to rent a car for a week - you can manage 110-120 EUR.
Prices for food. Dinner for two people will cost 30-60 EUR.
Plus excursions (from 30-60 EUR) and souvenirs.