Poland seems to have created a lot of postal stationery over the years. When I first visited Poland in 1980, most people didn't have telephones and the telephone system wasn't particularly reliable.
So the simple way of giving messages was to go into a post office and buy a letter card. A lot of them had great designs and the card only cost 20 groszy, plus the price of the postage. And they were used for business as well as personal messages. The backs were blank for the message.
I've put up pictures of a few. If anyone collects these things or has a particular interest in them, share it with us. We'd love to know a bit more.
see also
Tips on collecting
Polish stamps - exciting issues