I inkjet printed sheets of 2"x 3" business cards. My images are B&W. I used a stamper I bought at Staples the office supply store to create a self inking stamper that prints the word "Copyright" with my e-mail address and cell phone number.
The stamp makes it evident that it is a hand made print that I'm actually gifting someone. I made these because they are of supreme quality, and present my work well. I also have about 50 different cards so I have a sample of my work that I can carry with me in a credit card wallet at all times.
The cost and time required makes these small print unmarketable. All photographers that see my cards ask who made them, because they are so nice, and because they would like to do the same for their work.
I give these away as en-Fem-Ra to market and promote myself. It is a sample of my work, and also makes it clear that I'm also a fine art printer.
In a "Gallery Workshop" the business model presented is to do limited editions. This seems the best way to make your work a precious commodity of high value with the twist of collectability. Careful records are required and are useful for providence. When small editions sell rapidly then it is time to raise prices.
IMHO it is unwise to try and create a mass market with small prints. Hard to develop a following, a market, and most of all a reputation. Don't sell yourself short.
Also know that I have seen some remarkable work performed via small prints. This woman Sara used alternative process and each print was unique and hand made. Size is not the issue here. These prints were lovely to hold in the light in my hands. They created a beautiful experience.
Cal