They can join with or without referrals by simply downloading the App and entering their details, and their credit/debit card to start saving the Planet. They can nominate any participating ECO to benefit from their shopping or encourage their ECO to join. They can be referred by any member, Business, ECO or Ambassador. If they are referred by someone in an Erth ™ Ambassador network, part of their shopping will always go back to that network which cannot be changed.
