Cheap meals could include
I've just done an asda basket for £11.63. You could probably do this cheaper if you had an aldi or lidl nearby
Pasta shapes 41p
Long grain rice 48p
Italian passata 50p
Tomato puree 60p
Garlic 39p
Essentials wholemeal loaf x2 78p
1l milk £1
Curry powder 80p
Potatoes 2.5kg £1.25
Chickpeas 45p
6 eggs £1.45
Tuna in brine 55p
10 essentials Fishfinger 75p
2 x tins baked beans 54p
Essentials onions 55p
1kg mixed veg 72p
Jam 40p
With the above I would make
Jacket potatoes (micro if energy costs are an issue) with beans, or tuna or leftover curry x 3 meals
Potato and chickpea curry with rice x 2 meals
Scrambled eggs on toast or omelette with onions and potatoes x 2 meals
Tuna pasta (penne, froz veg, tin tomatoes, tin tuna, Tom puree) will stretch to 3 meals
Beans on toast x 2
Potato and veg soup, flavour with curry powder, salt and pepper x 3 meals
Fishfinger sandwich x2
Fishfingers mash and frozen veg x 2
Fried rice with onions, garlic, frozen veg x 2 meals
Jam on toast as required or could make a bit of rice pudding with some leftover rice, milk and jam
That would do 21 meals for a week, not exciting, not great for long term nutrition but doable for a few weeks.
Other cheap meals I would make are
Chili made with kidney beans, onion, garlic, paprika, chili powder and a squiry of tomato puree
Lentil curry
28p noodles with added froz veg or tomatoes and onions
I agree with others if you have £55 now you could take advantage of bulk buying ingredients which would be cheaper in the long run. People have mentioned too good to go and olio which can be great but can be a bit of a mystery bag.
Hope this is helpful. You have had some good advice on this thread.