Welcome to Listia! Digital delivery means you would not be actually mailing anything. You would be emailing it to them. Such as if you were auctioning off a recipe, photos, codes, coupon, poems, stuff like that- that u could email to the winner. That's what digital delivery is. :) Free shipping means you will ship the item (the shirt) to the winner- and you will pay for the shipping, which in this case would probably cost about $3 --give or take some cents. The smaller, and lighter the item- the cheaper the shipping costs. The larger_heavier the items, the more the cost to ship. (I use envelopes as often as possible. Boxes tend to cost more) also- international shipping cost more. "Winner pays exact" means that the winner of the auction will pay for shipping the item to them. The exact amount that the postal service would charge. Most people accept the shipping through PayPal-but some sellers will accept money orders or concealed cash. It's up to you. Flat rate means the winner again pays for the shipping of the item. However they pay one flat rate. Flat rate boxes are free (and are delivered to u for free from the website USPS.com) or pick them up free at the post office. The boxes n envelopes themselves are free. But the price to ship using them varies. Small box n envelops are about $5.95 I think. Med ones are about $11 and larger ones I think $15. --u can find exact prices online at USPS.com.
:) hope that helped ya a little!! If u need any more help feel free to message me. Thanks