The shopping list works fine, and it is very easy to use
. The problem however is, that there's no (useful) manual entry for it. The gerrit patch (g#1197) should fix this.
To use shopper, create a text file with your favourite editor, write down your shopping items, one per line, and save the file as "*.shopper". You can add categories by starting a line with the '#' sign. The usage of the plugin itself is rather self-explanatory.
Example shopper file: