A lot of coupons can be found on a product's website & be printed at home (library, etc). Current magazines can be got at library Friends stores for a dime or so. I have one of those big accordion notebooks with the whole alphabet, lots of room for coupons. Some folks classify by type (paper, frozen food, etc). Others use shoe boxes to sort, my notebook being too small. You probably know all that....

I've lived on the road during great sections of my life, & I've almost never eaten out. I wasn't dealing with children, tho. Only other adults. I had a really good cooler, sometimes one that ran off a DC auto plug. Usually had a couple of largest-possible Thermoses too. Always ate healthy, not elaborately, went la grande deli once a week or so. It takes planning & some initial investment, but over the years it more than paid for itself.