What about eBay? I don't understand the question.
If you're selling on eBay you'll still have all those costs. If you opt not to advertise anywhere else, you'll still have all the other costs discussed above, plus the listing fees and pay pal fees.
In addition to the other things mentioned, you'll also need packing materials, oxygen, heat or ice packs, bags, boxes... gets costly when you're shipping one or two things to each individual.
What about DOA/DAA policy? What happens when somebody files a claim with eBay because something you sent them was DOA etc?
Jenn