I'd raise the fee too. Most parents will gladly pay the $2-3 extra vs having to send their child a lunch. Food is important and it sounds like you serve great, healthy meals and that's a huge benefit to the kids!!
There are ways you could cut back/save though...only buy on sale, buy in bulk to last you until the next sale, make freezer meals so that nothing goes bad before you get a chance to use it, cut back to one fruit per meal/snack, pasta lunches 1-2x more often in the menu rotation, use bean dishes as a filler, buy cheaper cuts of meat and slow cook them so they'll still be super moist to chew etc
Also, don't feel guilty if you give them soup and sandwiches or even hot dogs once in awhile!! Nothing wrong with that when they are getting such healthy meals the other 4 days of the week![]()