You can invite your friends and earn rewards in-game! In fact, both the Mentor and the Apprentice are eligible to get rewards!

Simply get your friends to join you in Growtopia, be their mentor and convert them into a Growtopian!  

• You need to reach level 20 to become a Mentor.
• You can wrench any Growtopian who is between Levels 1-3 and select Add Apprentice to send a request for them to join your mentorship program. Note that Growtopians above Level 3 cannot be added as an apprentice.