Teespring is a marketplace of consumer designed products. The brand had initially began its venture to market custom designed t-shirts. It offered customers a way of selling self-designed T-shirts for fundraisers. They provided a great DIY online design tool for customers to create professional looking T-shirts and other printed garments. Teespring has then grown into a marketplace for entrepreneurial designers to sell their custom designed t-shirts for fundraising or charitable campaigns.
A number of Teespring clone websites like Bonfire, Sublimator also offer a slick online t-shirt designer and the ability to print a limited number of custom T-shirts. Recently all of them have added more and more custom print products like hats, other garments, etc.
If you like to create a website similar to Teespring and clone their business model, you can do so using iScripts Printlogic. Check out a live demo to see how it looks from the user perspective and admin perspectives. The tool allows you to customize the model with a few features but the others are available off the shelf.