I have seen you video on Shopify its very informative. I juz need small clarification...hope you would help me. How to add products to our collection? Can we use existing products in shopify and add to our collection? Or do we need to have them with us physically. How to change the price of the product. Can you throw some light on Print on Demand app on shopify for T shirt printing. As I have heard for T shirt printng we dont need any investment.