Welcome to Android Central! Do you actually have Cartwheel or the Target app installed, or are these appearing independently? Are they only occurring when you're browsing, or even on the homescreen, or when using other apps?
Independently. Do not have Target or Cartwheel app installed, or at least I didn't install it, and it does not show up in the list of Applications. Appearing in browsers, email, games, etc.
It sounds like some bit of adware that got installed unwittingly, alongside some other app. You might have to uninstall apps one by one until it goes away.