In Settings>Store Settings>SMS Settings, click on the (SMS Coverage and Costs)
Country / Network: Each country that is available to be sent too is listed, along with the networks it can be sent too.
Outbound Message Costs: 1 (one) outbound message credit
cost is valued at AU$0.22 (22 cents Australian). Each figure next to
the relevant country represents the proportion of that cost. As an
example, sending to Telstra Australia mobile costs $0.22 x 2 = $0.44 and
sending to Virgin Mobile is $0.22 x 0.8 = $0.17
The charges are billed monthly with your regular fees.
Please note that the above rates are approximate only and are subject to change without notice.