Airtime top up self

⦁    Dial #144# and press 'send‘ or ‘call’
⦁    Select 5 to buy ‘Top up and data bundles’
⦁    Select 1 for ‘Top up’
⦁    Select 1 to ‘Recharge own number’ 
⦁    Enter the amount of top up you want to buy in Leones
⦁    Enter your password and press 'send'
⦁    You will receive the confirmation message on your phone

This service is entirely free.