Hello @Memokoko and welcome to our community!
Can you please tell us where your camp is located? That way we can provide better ideas where to get a stroller.
You can always try ebay kleinanzeigen. There is a section where people give away stuff for free or in exchange for stuff they need. You can check it out here and maybe you find a stroller near your location:
https://***.ebay-kleinanzeigen.de/s-zu-verschenken/c192
Best regards,
Thorgen