Comment 3 for bug 1008309

Jason Conti (jconti) wrote :

Not disagreeing that this is confusing, but it does say right at the bottom of the 'Download your Humble Bundle' software center page:

To install the app once Ubuntu Software Center has opened click on the "Buy..." button, don't worry you won't be charged for it.

So just click Buy, no need to manually add the PPAs.