Asda have an offer on Innocent Smoothies ... £2 for any flavour. I didn't see any gold Superfood cartons in store but there's only a small selection in my local branch (Castle Point). They did have the scrummy breakfast one though. Available online to. You'd need to buy 13 litres to get over the minimum £25 spend mind you, so you'd need a big fridge.
They also had normal flavours of Pringles for 75p. Just to balance out the healthiness of the smoothies I suppose.