You figure shipping by getting the buyers zip code after the item sells than look it up on the website of whatever service you're using..usps, ups, fedex, etc.. Personally, I have an account with UPS. I figure my shipping, pay for it online, then print out a shipping label with addresses and all, then drop it off at the local pac & send on my way to work the next day. She charges me a dollar for handing it to the UPS guy. It's usually a good idea to insure an item too. Don't forget to add that to the shipping charges It's not much, I think about $1 per $100 worth of value. When you get the shipping charges off the shipping carriers website, it'll ask do you want insurance. Keep ion mind, there are a lot of know it alls and people who suffer from the same malady I do..RFN syndrome. So they put the payment in the mail before they even hear from you what the exact shipping charges are. I won't quibble over $2 but it can be aggrivating.
If your item does not reach the reserve, you do not have to sell the item, therefore you do not owe the sellers fees. That's why I don't bother with the item enhancements. You have to pay for those wehter or not the item sells.
You can have the buyer pay you through paypal,rather, they put the money in your paypal account. Paypal automatically deducts thier fees, then you can deposit it into your checking account yourself, or keep it in there service charge free or have it put on a paypal Visa card which you can then use as you would any other credit card becuase it is a regular visa card. You can only request a buyer pay you a certain way too. I've listed items as Paypal only or paypal, M.O. only etc. A lot of people have trouble following directions. I've recieved personal checks in the mail after specifying Paypal or M.O. only. Then they had to wait 9 days for the funds to clear my account. They were ok with that but still if they'd have followed my directions, they'd have gotten their merchandise 9 days sooner. Never....NEVER ship someones merchandise until their funds are in your hand/account. I know most people are trustworthy but I've witnessed too many heartbreak stories to take the chance. Look at the one in our own classified section, poor guy just got jacked plain and simple. Just get in there and sell some stuff, you'll figure it all out.