If you want to do print on demand business and if you are looking for platforms where you do not have to integrate third party manufacturing company or do not have to pay for upfront costs, Redbubble and Zazzle are the popular options. If you have never tried any of these platforms and if you are very new to print on demand business, I suggest you to try both platform and work hard on selling your print on demand products on both platforms. Once you start generating sales, you can focus more on the one where you are comparatively successful. By the way, have you tried them, which one is better.