To clarify, showcase sites are submitted to us by customers, we don't simply post up sites without permission or generally pursue people to use their sites, but hopefully we'll get something up soon as the showcase is due to be updated. AppThemes has been around for years, so the statement about our customers is true :)
In answer to your questions:
1. The
theme settings allow you to select from the available currencies (supported by PayPal) in the currency dropdown menu, but using others would require either customization, or you can purchase
other payment gateways from the AppThemes marketplace which may support your currency if it is not there by default.
2. Yes you can allow free posting if you wish. Thanks.