How do I get a German number for SMS verification when registering in the app?

[Yvette00]

While passing through Germany, I stopped at a gas station that offered a generous discount on coffee and fuel for registering in their app. Activating the profile required only a local SMS code. I used a free German number from the https://onlinesim.io/free_numbers/germany page and refreshed the inbox. The discount coupon worked immediately at the checkout, making the brief stop even more pleasant.