As a former "fussy child" I never ate school dinners, they are often not the food you want to force children to eat! My mum insisting that I ate all the food in front of me (always, always unhealthy), resulted in bulimia. I am fairly strict on most things but if my kids will eat healthy protein, 3 vegetables and brown carbs at dinner then I am happy to allow some choice. My bad experience clouds things though I imagine.
I'm still considered unreasonably fussy by my mum. My dinner last night was chicken, olives, peppers and quinoa - hers was most probably her shepherd's pie, fat drips off the fork with every bite. She will lecture me on my eating and my children's food whilst being 22 stone and having multiple health issues because of her weight and not see the irony.
Give children access to good, nutritious food and the chance to make healthy choices. I honestly don't see the benefit of forcing food if they would happily eat a healthier option.
Anyway, cheap lunch ideas. Buy a big pot of natural yogurt, cheap in season fruit (we did plums and apples this week) and something to help flavour it (we used cinnamon but honey works well).
Carrot and cucumber sticks with hummous is very cheap.
Crackers with a dip.
Oat muffins - also freezable which is handy. Oats in general are good as a cheap, filling option
Spring rolls from a Chinese store are incredibly cheap and filling. £2.75 for 100 at ours! Noodles and rice are cheaper there too if you have access to such a store
Pitta pockets - fun for children or make their own
Pasta will probably always win as the cheapest option. Fruity pasta is a huge hit in our house and very cheap!
My sons secondary are doing no more fsm choices, just a packed lunch provided by them so we are having to do our own too. The packed lunch is a sandwich, crisps, fruit and biscuit. Not awful considering it's free but not something I'd like him to have each day from now - December.