Ads are awful. It is currently a one-time purchase. Edit: this is one more thing that others were doing wrong.

Edit: Google ads are inane in my localization. You mostly get adult lines and "you caught a virus" scams despite opting out. Google doesn't seem to do anything about it despite complaints. I get paid because I removed the ads (even from demo version) and I do it gladly. Good riddance.

Reminds me of the time an ad managed to somehow break out of its boundaries and present the user with a popup. It still amazes me, this was Google Adsense for Android, but I saw it with my own eyes. And guess who received the bad reviews..