PrePay
http://www.safaricom.co.ke/index.php?id=168

The Safaricom PrePay service allows the freedom and flexibility to pay as you use by topping up your account with Safaricom recharge vouchers/scratch cards. Choose from our wide range of recharge methods and top-up denominations to suit your budget.

Recharge Methods

We have designed various flexible and convenient ways for our customers to recharge. If you run out of units, you need not worry.

These recharge methods have been designed with you in mind. It doesn’t matter where you are, but you won’t be without credit for long.