There ain't no such thing as a free lunch, and quality is often proportionate to the price paid. Think yourself lucky it was only adverts, not malware targeting your PC.
This is why I always read terms of us and or end user license agreements. 99% of the time an app that uses ads to provide for free lists it in there. The only ones that won't list it in those docs will be ones using malware to try and get personal info or something you would not willingly share with others.
