Depends on what you've downloaded onto your smarty. Most free and costing apps will state in fine print within the apps home page wither or not this particular app has ads within the app. Knowing this, apparently you've down loaded an app or several apps which will constantly send you unwanted ads. I would research what have been downloaded and remove those apps which these ads are associated with.
However, you can adjust this within the app's settings (apps manager) just to turn the app off and systematically rule out any newly added app/s which could be the cause for these unwanted ads.