Podcast Addict is a free ad-supported app. You can remove the ad banner with a one-time In-App Purchase if you wish.
You can also support the development of the app by subscribing to Podcast Addict Premium.
Still, some users are contacting me to find out how they can make an additional donation to support the app.
Unfortunately, Google only allow a fixed subscription rate for now, so you cannot customize your subscription amount.
Therefore, if you want to support the app development you can use one of the following options, but you should understand that these donations will not give you access to additional feature in the app.