Panasonic RP-HS34 Water/Sweat Resistant Sports Clip Headphones £5 @ Tesco In Store & Onlinehttp://www.tesco.com/direct/panasonic-sports-rphs34-headphones-blue/444-4362.prd
Not a bad price for half-decent earphones for commuting or running. If they get damaged no big loss.
Had lots in stock in Tesco Sandhurst in blue and red.
£5 listings at Amazon are out of stock, in stock listings currently at ~£7.40 (also on ebay)