I get nags to upgrade to something I couldn't care less about, in an app I paid to avoid these ads and nags, every time I open the app (i.e. multiple times per day) on "promo" days (i.e. any US holiday)
These nags have also been disingenuous, because the price will usually go up on "promo" days so that Apollo advertises a "special deal" that is basically the price it's always been before. It's advertised with a full-screen popup upon opening the app (or while using the app)
If it was no big deal and nobody minded, there wouldn't be a slew of posts complaining about it every time, and the app's author wouldn't consistently ignore these posts and comments as he has done every time while always answering praise and positive comments in the same threads and subreddits.
Selling me something to remove all ads and then showing me your own ads anyway is dishonest. Either mention this at the time of payment, or make it opt-in like virtually every other company I deal with (aka "do you want our marketing material?")