GIN means "get it now". Since you are new you don'thave that option yet. It just simply means you can set a point " price" limit where someone can end your auction by giving you those points.
Free shipping means you will pay postal cost. You can generally get away with it costing 5-6$ at the flat rate box/envelope at USPS. That will come with free tracking and 50$ insurance. You WANT the tracking. Is your only defense against nasties saying they did not get item and filing to keep the points. Listia will decide in their favor if no tracking to prove delivery. CUTE BAG BTW.
When you mail it now all first class has tracking on it. Thats better because you will get a tracking number to give the winner so they can track it and know when they will get it. Nice auction