11.5% of "free shopping apps sell in-app purchases or subscriptions", that spunned my curiosity.

What could be those apps:

- resale/second hand apps that offer boosts to be seen?

- apps that sell alert systems when a price is dropping?

- grocery/listing apps that sell "no ads" functionalities?

- gated brands with VIP things?

Yet, 11.5% looks enormous. I may be old.