Someone from the team answered that they make money from the retailers. Zeex is getting paid by retailers because Zeex is used as the distribution platform
Thats right.
And Zeex will not charge any additional fees. I found this reply:
As a user, the only fees you will experience are network fees related to the execution of the smart contract (aka gas), Zeex itself does not charge any fee for conversion.
If you have any more questions feel free to ask!
Rafi Glantz- Zeex Community Manager