https://www.paidmembershipspro.com/add-ons/pmpro-lightweight-affiliate-tracking/

Create affiliate accounts with unique referrer URLs to track membership checkouts.Admin creates affiliate account and code.If affiliate code is passed as a parameter, a cookie is set for the specified number of days.If a cookie is present after checkout, the order is awarded to the affiliate.Reports in the admin, showing orders for each affiliate.Associate an affiliate with a user to give that user access to view reports.

Changelog

* ENHANCEMENT: Updating `` tags to `` tags for better accessibility. #51 (@kimwhite)

* BUG FIX: Fixed a warning on the reports page when the affiliate name was missing from the report. #52 (@andrewlimaza)

* BUG FIX: Fixed an issue with exporting the affiliates CSV wouldn't include the affiliates name. #52 (@andrewlimaza)

* REFACTOR: Now using the `pmpro_default_discount_code` filter for sites using PMPro v3.0+ instead of setting discount code by altering request variables. #50 (@dparker1005)