I do bulk orders with Printeez (100 to 500 t-shirts for me is my typical order) which they keep in inventory and ship the items for me (I linked my Shopify with a ShipStation key that they provided me with - pretty easy to do). Which means I also get better prices on quantity and shipping rates are also very competitive - certainly better than if I shipped the orders myself and it saves me time at the end of the day! Before I run out of T-Shirts I replace an order - turn around time is quick too. I think they will be integrating Shopify soon but I like this way of doing it because the margins are better, even though it requires a minimum investment to start, which is okay for me! Hope this helps!