Cost of ads
It is a Wikipedia like system : free of charge, but if someone who has found himself satisfied with the service rendered, he is free to participate in the “on-board crate”.
So, when a seller closes the ad, he is asked if the platform contributed to his sale. If he tells yes, he is offered to make a donation (totally optional) he even chooses the amount.
Face price and currency
This feature is being re-worked, so the currency change is temporarily disabled. It will be back online quickly and will allow conversion between EUR, USD, GBP, AUD.
Whatever the case, ads can already be created in these currencies, only the conversion to the display is not activated at the moment.