One of my favourite meals is corned beef hash. You can make it for only 2.5-3 syns a serving. I have been making it like this for years - the only difference is now I use a smaller tin of lean corned beef (Princes 200g is 4 syns for the tin). Pre slimming world I used a standard 340g tin just for the 2 of us.
200g lean corned beef cut into smallish dice
2-3 large potatoes cut into dice and cooked until tender, then drained.
2 medium onions chopped
1-2 tablespoons Branston Pickle (1 syn per tbs) or any similar pickle
Saute the onion in the frylight until softened
Add the potato and corned beef and fry until starting to turn crispy and brown. The corned beef and potato should start beaking down and mixing together. When warmed through add the branston pickle. Continue to fry for another couple of minutes, mixing well.
Season with salt and pepper and serve with a selection of veg. We usually have baked beans and tinned peas cos that's what my husband likes, but you could use tomatoes, mushrooms, peas, carrots etc.