ShippingIn the auction choices, be sure to indicate that "buyer pays shipping." If you already know how much that cost will be for your item, include that information in the description.
Remember the cost of packaging as well as the postage, and also try to minimize the time that it will take you to package your item and drop it off for shipment.
If you have a choice, sell small items rather than large ones. Sell items that will fit in a standard size box that you could send parcel post, rather than selling furniture or pianos. And better still, in the US, sell items that will fit in a flat-rate priority mail envelope.
In the US, for an item that could cost $2 or more to mail first class, you are better off sending it in a flat-rate priority mail envelope for $3.20. If you went with first class, you would end up spending nearly $1 for a padded envelope, which would add weight and raise the postage cost. Even if the first class postage would be less than $2, you sitll might be better off with priority mail because the cardboard flat-rate envelope provides good protection for paper goods, like comic books, and your package is likely to arrive sooner at its destination, with more careful handling.
Also, with flat-rate priority mail, you know the shipping cost right away without going to the trouble of weighing -- if it fits in the mailer, then regardless of weight, the cost of $3.20. This gives you the opportunity to use the shipping cost as an incentive for people to bid on more than one item from you.
In my case, if the buyer is getting one comic or five, the shipping price is $3.20, because that many can fit in a single flat-rate envirope. When the typical winning bid for a comic might be $2.00 to $10.00, saving on shipping can be a strong incentive for someone to bid on more than one from the same person, which helps drive up bids, and also greatly simplifies my logistics. For 45 comic book auctions, I might end up having to ship just 15 packages (and just keep track of 15 customers).
But priority mail isn't the only way to use shipping charges as an incentive. You can make special offers in your product description -- for instance, free shipping to anyone buying a certain number of items. Or you might, in followup email messages to winners of your auctions, offer those individuals a special break on shipping costs on future purchases of theirs from you (either from Ebay or arranged directly between you by email).
The importance of shipping cost as an incentive or disincentive varies widely. Some people will pay without hesitation shipping charges that are equal to the cost of the goods, or even double the cost, perhaps because the item you are selling is difficult to find or perhaps because the buyer lives in an isolated area or for one reason or another finds it difficult to get to physical stores where they could find anything comparable. Other people will drive many miles to pick the goods in person and thereby save a few dollars in shipping cost. Be flexible and understanding.