Hi Daisy - I'll watch this with interest as we're going to s/c in Italy soon.
Are you staying in s/c accommodation? In which case, will you really need to eat out for breakfast? You could venture out early for bread/croissants/pain au chocolat and eat in instead.
And if you're watching the pennies, you could always take a baguettes with you for lunch - lots of resorts have picnic rooms (marked on the piste map).
France has a reputation of being expensive, with the exchange rate making it worst.
If you are going to eat out, you'll find better value if you do that at lunchtime, although resort supermarkets tend to be very pricey. The tourist menus (2/3 courses) are usually fairly good value - I haven't been to France for a while so not sure what they may be now.
If you're driving down (which you're probably not), then of course you could either take some M&S-type ready meals with you or stop off in a French hypermarket to stock up.
If you're flying, some pasta and those pasta sauces in soft packets would make some meals.
(I'm assuming you're concerned about the cost, so sorry if this is all really patronising!)