Packed lunches can definitely be cheaper, and healthier.
My 3 have mainly-organic packed lunches and they cost loads less than school meals.
Sandwiches - home-made bread made with organic flour (bread costs less than 10p per person)
sandwich filling - varies but would never be more than 80p even for premium organic meat. Many fillings are veggie which are much cheaper, and could cost as little as 10-20p. Today for example was peanut butter - a smear even of organic peanut butter is hardly expensive!
Sometimes it's not sandwiches but another savoury - e.g. home-made pizza, really cheap.
home-made small 'treat' (flapjack, muffin, cake etc) - anything from 10-50p. Again, mainly organic ingredients.
Fruit - 2 portions, costing probably 30p each for organic.
So, it could be anything from 90p-£2.00 depending on what combination of things they have. I would say it averages more like £1.30-1.50. Obviously, choosing non-organic would bring this down a lot, so someone on a really tight budget could do it for very little.
And it's no hassle at all - I can make up to 5 in 10 minutes!