The table below shows the number of messages allowed for each of the SMS tiers. When you send more SMS messages than included in your subscription plan, you will be reminded to upgrade to the new tier in order for more of your customers to receive your messages. Once you get past 2,000 messages included in your monthly plan, the additional messages are billed at $0.03 per message.
For example, for 2,500 messages a month, you will pay 89.95 for 2,000 messages, and the remainder 500 messages will be billed $0.03 * 500 messages =$15.
This totals to $89.95 + $15 = $104.95.