What's wrong with tomato and mayonnaise sandwiches? I thought everyone ate them! Also, cucumber and mayonnaise (best with a sprinkling of black pepper!).
We grew up on devilled ham, canned corned beef, vienna sausages.
My personal favourite "cheap" food is creamed egg and cheese on toast : hard cooked eggs (chopped up) and shredded cheddar cheese added to a white sauce, served on toast with a sprinkle of paprika. My husband thinks this is absolutely disgusting but I love it.
(You guys can keep the sardines!)
Yvonne