SimpleTexting - Pick Plan and Update Payment.
2nd click on Settings in bottom left hand corner.
3rd. Click on Billing and then Change or Add Plan.
4th. Here you can choose Monthly or Annually. Click the radio button on the right for the amount of texting you will be using monthly. Make sure you update plan in lower left hand corner.
Here also is that breakdown regarding credits - the only other thing to know is that incoming SMS messages are free and incoming MMS messages are 2 credits each:
Standard SMS - 160 character max / 1 credit per message
Extended SMS - 306 character max / 2 credits per message
MMS (Multimedia Messaging Service) - 1600 character max / 3 credits per message
5th. You may need to click on setting -billing again on the left. Now we need to put in your credit card information.
6th Add credit card information