As Sainsbury’s kindly points out (for the mathematically challenged), £10 gets you £20, £20 equates to £40, and £50 doubles to a massive £100!
Just fill in this form to get your free SIM, and top up by at least £5 within 30 days to get your free credit.
And there’s more! Top up by March 31 to enter a prize draw to win one of five free Samsung Galaxy Note 4s.
(Thanks to goonertillidie at HUKD)