Edit: as the other comment mentions, most banks where you have an account offer this for free. My local UPS store where I have a mailbox also offers the service to me for free.
GP is probably not in Germany, but just an example of why I’d be uninterested in getting something notarized here unless my continued freedom and/or good fortune depended upon it:
American notary: someone who doesn’t have a history of fraud, sat through a workshop and passed a test.
German Notar: a very specialized lawyer, bills like a very specialized lawyer.
Theoretically, you can get stuff notarized at US embassies and consulates, for $50 and an appointment, must bring your own witness(es). That of course has not been an option much of the past year.
In the USA, in Marin County, I was charged $25 per document. The guy doing it was adding a finger print, which is not a bad idea if the originator of the document is present.
Edit: as the other comment mentions, most banks where you have an account offer this for free. My local UPS store where I have a mailbox also offers the service to me for free.