Amazing price here, ASDA in Worcester had the Venom Nintendo Switch Power Supply for just £3.75 and also Stealth Nintendo Switch Travel Cases for only £1. These are really low prices for useful products even if you don't need them right now.
These prices could be national but likely to be a a few stores here and there as with most of these Special Price items at ASDA. On Amazon the Power Supply is £14.99.
The Worcester store also had other tech stuff on offer like Turtle Beach headphones for £3.25 and £6.50 (see comments for images).