Mark as to suggestions on cheap food
( I just finished spending the whole summer sailing around Nice).
Right now Peaches are in season, lowest ever pricing. Secondly try and get out of teh marina and shop in Geant or Carrefore ( there big pricing differences between local supermarkets and the giants.).
Secondly take the train to Ventimilla in Italy from time to time, cheap food
and cheaper drink. ( its where the french go to buy boozes and cigs).
Also in my experience search out the restuarants a road or two back from the beach, ( Cagnes is very good for this), the Formules for lunch usually start at 6-7 euros, and A very good lunch ( three courses can be gotton for 10-12).
The cafe in the train station in Nice is also very cheap.
If you do stay for longer ,soon the restaurents will switch to off season menus and things get cheaper again.
Another suggestion is to buy a cheap french electric grill
( about 18 euros in Geant). Great for frying steak, prawns, etc and keeps the heat out of the boat, put it on the dock
it in. You can get nice steak for 3 euros each plus some a tin of potatoes ( slice them, fry on the grill
with some chopped onion). then make a roquefort sauce, heat some roquefort, add a little creme fraiche and a drop of djion mustard. Bliss a beautiful meal for about 5 euros.