OK, ditch the sugar, a bit less fruit, a bit more…other stuff. Maybe I will throw in a leek, some fish and some nuts.
I checked Tesco’s website after you flagged this to me but the cheapest 12pack of free range eggs are at the price I say; fruit could be cheaper but the very cheapest fruit is usually pretty minging. Porridge too could be cheaper if I did something drastic like bought it on Amazon but these are just Quaker Oats, nothing special! So in short prices aren’t the absolute cheapest possible but it’s not like I’m buying absurd “Whole Foods”/”Waitrose” piffle either.
You should be able to eat ‘healthily’ for a fiver a day. Protein is most expensive, so things like tuna, eggs, milk, turkey, beans/pulses are all good as they don’t cost too much.
Carbs are cheap, bulk buy oats and potatoes. Cheap veg is ok also.
Fats you can get from olive oil and nuts.