About licenses, and adding products to google play ?

About codecanyon products and licenses, this is my second question continues my first question …

Is these licenses costs anything ? Number of end products means one user can only add one product to google play ?

And one important question, if someone got the app and already added it to google play, and i got it , can i upload the same app on google play ? If not, why people buy it ? What they do with it ?