Not to be outdone by the Toffifee (100G) and Toblerone (170G) for around a Pound at various places, I have pleasure in finding Granny's Favourite box of 3 Nestle Walnut Whips (98G) for a single Pound in Poundland, both instore and online (+postage).
I personally don't like the Walnut part, so I throw that to the ducks, but the rest or the Whip is lovely.
Please pig out responsibly.
Other places have them for £1.50 and a box of 6 for £2.49.
Edit: It's been pointed out that apparently these are for anyone, not just Grannies