That's if you choose to use a fixed or free shipping cost. Since I started in August last year, I've primarily been using calculated shipping as a method to avoid getting burned. This requires you to have a shipping box in mind for the set you're selling already, and the packing materials on hand to put it all together and weigh it. Once you have box dimensions and final weight, you plug that info into the Calculated Shipping fields.... then using your own postal/zip code, ebay Calculates for the buyer based off their location in relation to yours, and the service that's been selected.
I find this typically results in fairly accurate shipping quotes for the buyer, but often it's a little bit higher than what you actually pay if you use the at-home label printing through paypal, as you save a little percentage there. This usually ends up covering the shipping portion of your ebay fees, which is nice.
Highly recommend BIN perhaps with Best Offer attached. That's usually how I sell all my used sets. Check BP, check BL, check ebay sold listings.... come up with a price that's about 10% above the average rate, add Best Offer, and negotiate with buyers up to 15-20% off my asking price. This usually lands right around my target profit margin. Pick a system and try to stick with it.
IF you have an incredibly hot and popular item, put it on auction and hope for the best, but generally speaking in my experience, auctions will end lower than you hoped for, and there's nothing you can do about it once it's done. At least with a low Best Offer you can outright decline, or choose to haggle. Once you're sitting on a healthy profit margin it might be less of a risk to list more as auctions, but when you're starting out it's a sure fire way to put yourself into the negative I think.