After removing "unity-lens-shopping" remain some annoying tips from the Software Center.
To hide them, go to:
Dash Home, Search applications, Filter results, Sources and then sets to "Local Apps".
After new login, the filter is reset. To do something for real, it seems that this works fine:
gsettings set com.canonical.Unity.ApplicationsLens display-available-apps false
Ubuntu 13.04 have new package called "unity-tweak-tool". Try it.