I cannot say if I was too cheap to rent a Deutsche Telekom approved computer device, ie modem, but back in the day when I moved to Germany I didn’t bother. I had a modem and I didn’t think that I should be forced to rent one of theirs. This was back in the day when monopolies could force you to rent phones from them.
It may be a moral victory but it really was a moot point. I am not sure there was another computer in all of Germany that I wanted to connect to, but I guess it made me feel like a rebel.