There's a host of websites and/or fulfillment centers which you can work with to get your products out there such as Zazzle, Cafe Press, Spreadshirt, etc. It really depends on what you are looking to do, i.e. do you want to create a 'brick-and-mortar' storefront and/or do you want to just create a web presence? If it's just the latter creating stores on the forementioned websites is a good place to start since it's free and you can begin to put your designs up and see if you start selling. If your products do sell then that would warrant further investigation about methods of bringing your production, in-house, and eliminating the need to outsource your printing.