When you click the 'Pay by PayPal' option, you will be taken to the PayPal site.

If you have a PayPal account
Login to your PayPal account with your email address and password. Review and confirm the payment details before making the payment

If you don't have a PayPal account or have never used PayPal before
Enter your credit card billing details in the form that shows up when you reach this section. If you don't see a form and wish to continue paying by credit card, click on the link that states:

Don't have a PayPal account?
Use your credit card or bank account (where available). Continue

After the payment has been made, you will be returned to a page on Directory Maximizer where you should receive a 'Transaction Complete' message.