... In my postal system (which is currently not functioning thanks to a labour dispute) that lets me send three 4.7x7 prints at a normal letter rate.
I found some funny thing in my postal system. Letters sent international may be a bit bigger than letter sent within Germany. Today I sent some images for the alternative print exchange and the same image to someone in Germany. The envelope was just a bit too big to be sent as a letter within Germany which means that sending that image international was cheaper than sending the same size within Germany.