Is this application free or not?

All basic functions are free forever. 

Advanced functions require a subscription.

Advanced functions are:

• - usage of Sale and Purchase prices;
• - more than 2 stores;
• - more than 10 Customers or Suppliers;
• - creation of Custom Fields
• - schedule automatic backups in Stock and Inventory Simple;
• - more than 1 user in the online version (Stock and Inventory Online)