apologize for it took me some time to respond. To answer your question, about ten years ago I have spend the sum of approximately 700€ for about one hundred such postcards. Individual prices varied, those with the LZ-85 used to be the most expensive ones, didn't buy any.
Such postcards provide the best documentation of what Thessaloniki used to be at the beginning of the twentieth century. Of course the city has changed a lot since, with the city-centre being destroyed by the great fire of 1917, while the then suburbs were rebuild mostly in the sixties. Unfortunately most of the beautiful mansions were torn down and replaced by blocks of flats, what a disgrace.
And yes, have read about LZ-104 and its epic flight over Africa, as well as its final flight and loss over the Adriatic.
Happy New Year mates.