People need to do what they want with their creations - sell them, give them away to all, give them to only certain people, give them as a limited freebie.  Those who are interested can do whatever's needed (or not needed) to get the item.  That said - 

One thought is to consider rewarding people who have bought in the past in addition to those who buy today.   There are some content creators who have a set of freebies for those who have bought something at some point.

As I understand your current plan for these extras, someone who's bought a lot in the past doesn't get these freebies, while someone who buys one  item does.  So they can just buy one little thing and get a freebie, while those who've bought a bunch don't.  Now, that may be the idea, to get new sales.  If so, that's certainly your choice and we all need to abide by it.  :)

Cheers,
Alisa

RETIRED HiveWire 3D QAV Director