WHMCS
Feeds > productpricing_monthly.php
Return monthly value for any billing cycle.
Ex: The annually price for a product is 24.00$. The script will display 2.00$ as it's the monthly value of the annually billing cycle.
Aff.php
Custom affiliate landing page. Can redirect to any page of your site using the $page variable.
Ex: https://www.mydomain.xxx/whmcs/aff.php?aff=13&page=hosting.php