Nature Valley Bars - overpriced (but v tasty) cereal bars - either oat & honey, oat and dark chocolate, maple syrup or multiple flavour packs.
Normally approx. £2.40+ in various supermarkets (although often on 2 packs for £4 offers), Morrisons in-store and online selling these for the cheapest I've seen ever at £1 for 5 x 2 bar packs.
Despite me buying armfuls yesterday, still plenty on the shelves today when I was sent to the shops again!
Seems a decent saving for those who would've bought them anyway.