Thats ok and i know about that, but...
Most Customers of any Android App (not only "eset") will use the way by downloading the App from "Google Play" - thats a fact.
So if eset want to be in the market/to sell their product and not just supporting Free Versions (and im quit shure they will) they must think about Ways to easily change from a Adroid Free App to a Pay/Premium App.
And in case of european (specially German) Users, they do not use Creditcards that often. So just offering Creditcard Payment is a silly idea ....
And in the end, if this is a Problem for a new eset Customer like me, where else should i ask for help then in a eset Forum ? I also asked the eset support, but they dont work on Weekend - and if some other german customers read my Question (while having the same Problem) it does not help them, when i get find the Answer by eset support - it should be in here, where everybody can read it, or ?
Because this is a active part of what you call "support of ESET software in a eset Forum, dont you think so ?
So for all the Germans out there:
If you dont have a Creditcard, but want to chage your Free Eset Version into a Premium Account, just buy a "PrePaid" Google Play Card (the are in 15/25.. Euro) in any Store or Gasstation ("Tankstelle") and it will work easy