Amazon is rolling out Amazon Dash in the UK. This is a button which you set up to order anything off Amazon when pressed. The buttons are £4.99, which reduces to £0 when used, but if you choose the 3-5 day delivery option, you still get £1 credit for Amazon digital purchases.
Need three Dash buttons? Make three separate orders and check 3-5 day delivery on each one.
Notes: The buttons only become £0 when first used, but if I understand correctly they can be set up to order anything at all on Amazon.