Some of the common places to marketing matted images are through retail stores, street markets, art and photography exhibitions, craft shows and find raising projects. You will find a lot of competition with any of these alternatives, so you must be prepared to provide the best possible product at the least price. Assuming you have a photo or artwork that is readily sellable, there are ways to present that product to the end user in a highly attractive manner.
I can't tell you how many e-mails I've received from young wanna-be photographers asking me "What's the best way to become a professional photographer". So... I've decided to take the time to write down my suggestions on perusing a career in commercial photography.