Re: Frustrated!!
Those definitely come from an app you installed. You need to find the app and uninstall it. Usual culprits are shady games, file manager apps, chinese launchers, etc. Of course, if you side-loaded any apps from non-reputable sources, that also exposed you to having adware installed on your phone.
Run an Adware scanner (like Lookout's app from the Play Store) and see if that can pin-point which app it is coming from. If the ad shows up with a charging lockscreen or something like that, there should be a settings icon somewhere before it pops up.
Galaxy Apps 'ads' don't show up as that, they show up as recommendations and as a notification in your notification bar; you wouldn't see any specific app info unless you tapped the notification (which would take you to the Galaxy Apps app, not a random site). Those can be turned off in Galaxy Apps settings if you don't want to receive recommendations/promotions.