I can ship one dvd or video game, well packed, for 1.26 first class or like 1.45 media mail. [The rates have gone up in the last year or so, I don't recall if that cost is before the new rates or after.] Anyway, well under two bucks. Delivery confirmation isn't required by Half.com, though it is suggested--I have only used it once, when I sold a dvd for 60 bucks, and then I didn't mind the extra fifty cents or whatever.
Back when I was selling a lot of stuff, I bought a box of bubblewrap, a roll of kraft paper, and a roll of clear shipping tape for under 20 bucks, and I have been using the bubblewrap and tape ever since. I have had to buy another roll of paper, but that's 1.50 for 60 square yards or so. So my shipping overhead is very low. I don't have a problem with, say, shipping of 3-4 dollars First Class, and 4-5 bucks Priority Mail [less overhead for that, because the Post Office GIVES you all the priority supplies for free.] Three bucks is more than fair, and there's a little jiggle room, because now that the USPS has gone to 'zones,', it's not just a flat rate.
Half.com's commission of generally 15% does seem a little high, but they do give a shipping credit, and there's no charge for listing stuff for as long as you have it, so I've found it worth it, for the 'regular' stuff, just to post it and let it sell, rather than fooling around with an auction.
Asa buyer, I have found a few good deals--I got my wife a CD she wanted, brand new in package, for around ten bucks shipped. Plus fixed shipping-the rates aren't that competitive, but they are at least consistent and fair.