I bought a whole box of vinyl record and there were about 10-15 German Lp albums and inside one of them I found 3 German Phonocards stuffed inside. Not sure about the dates of these but looking at the vehicles in one of the pictures it looks as if they were made in the 1950's. Each one says Schallbildkarte on them.
1. The first one is of Burg Rheinstein ( Castle Rheinstein). It plays Mitternachts-Blues. It also says Bestell-Nr. 18/32
2. The second one is of Munchen Karlsplatz. It plays The River Kwai March. This one has Bestell-Nr. 15/31
3. The last one is of Heidelberg Am Neckar. It plays Wo meine Sonne scheint. It has Bestell-Nr. 14/16.
The only other phonocards I have found that are similar are ones that have French images on them and they are listed on Ebay for $78.00. Then I found some listed on I think the German Ebay, but everything was in German and couldn't figure out the currency converter to figured out how much they are listed at.