The humble postcard was actually my most profitable result for a period when I was trying out a photography business. Since I don’t like photographing people I had to try and go along with selling my own prints, it is much easier to turn people into a $5 sale than a $300 sale, I learned. But I also used online print on demand to get the postcards at an affordable rate. I have also used these for advertising flyers before alongside the 4x6” photo prints.