A shortcode can be set up in three ways
1. Toll-free: Where the company is billed for the outgoing SMS but not charged to receive and the end-user is not charged to send or receive. Here the cost of a message depends on how much you credit your Africa's Talking account.
Please see the link below with the cost of SMS.
2. Standard rated: The end-user is billed the normal SMS rate to send or receive a message, the shortcode owner decides at what point they would like their customers to be billed. For this type of shortcode the organization is not billed for the SMS.
3. Premium rated: THe end user is billed above the normal SMS rate and you generate revenue. (This is only available on Safaricom) For this type of shortcode the organization is not billed for the SMS.