What is the difference between the pay-as-you-go plan and the email-based plan?

What is the difference between the pay-as-you-go plan and the email-based plan?

Before choosing a plan for your organization, you need to know the difference between the plans. Difference between pay-as-you-go plan and the email-based plan are,
  1. The pay-as-you-go plan allows unlimited contacts, while the email-based plan only allows half as many contacts as the number of emails purchased.
  2. The email-based plan is on a recurring payment cycle, meaning that the payment is taken automatically each cycle. The pay-as-you-go plan is not on a recurring cycle.