TexansPittsTees.com is still relatively new to Shopify, we use a Print on Demand service for our t-shirt shop. Is that compatible with the requirements of the Walmart market places, shipping guidelines as the print on demand usually takes a few days to fulfill order? I know there is a vetting process to go through, and we have a Facebook connection and have done Facebook ads and promotions but still have not made our first sale. So not sure if we have the ecommerce experience yet, but looking for input. Also, don't have upc's associated with our products yet, is there a tutorial or video that shows you how to do that? Thanks any feedback is appreciated!