I think it was Mrs Beeton who said the cheapest meal was a piece of toast between two pieces of bread that were spread with butter. I don’t see the point, just have a couple of rounds of toast, spread with whatever.
If you’re really desperate crumble a Bovril cube into a soup bowl and fill up with boiling water then dip your toast into that. You can also grow herbs on a windowsill, then chop herbs like basil into your saucepan, add a Bovril cube and simmer for 5 minutes to make a soup to dip your toast in. If you have a onion lurking in the fridge, chop it as small as possible, fry it in a little oil, add herbs, salt, your Bovril cube and water, then after the onion is soft, simmer for 30 minutes for a nourishing soup.