This can be very controversial, but a QSL manager should not be paid for QSL/postage by someone that requests QSL. If a station operator is not able to do his own QSL this operator should pay the QSL manager for his work. Otherwise there are systems like eQSL and LOTW that are free to access. At least the station operator in question can send a log monthly to someone that manage his accounts if they are not able to get on the internet. Such a station should clearly write on his QRZ page that a paper QSL is not possible.
I know there are a lot of QSL managers in the world that do excellent work. They spend a lot of time answering QSL post most time with a lot of expenses which cannot always be covered. But is it really neccesarry? Decide for yourself! Of course it's always your own decision to make a donation or not!
Link: The QSL manager's society