A few weeks ago, a customer sent me a message after receiving her package saying that she felt it was unfair that I had charged more for shipping than the postage on the package. She wasn't angry or rude about it, she was simply coming to me with concerns and after I explained the other side of it to her, she understood and no longer felt like I had taken advantage of her. I thought perhaps there were other users who feel cheated and might benefit from the same explanation.
The actual postage is among the cheapest things about shipping a package. There's the package itself, of course, as well as the mylar bags. Using mylar can actually be a great expense, as it would be unwise of me to have 10,000 mylar bags lying around, so I can't take advantage of bulk discounts when I order my bags; worse still, I can't have a constant stream of deliveries of mylar bags coming to me without ALSO looking suspicious, so I have to find a balance between the two extremes. Then there's the time I spend preparing each package, which can take anywhere from 5 minutes to an hour depending on any special circumstances; that's counting cleaning off residue and fingerprints, as well as any stealth tactics involved(which for most of my products isn't difficult, but for other vendors this can be a serious undertaking). Once a package is prepared and the postage put on it, though, there's still the aspect of getting it into the hands of the postal service. This aspect involves having a mental map of a shit-ton of post offices and drop-off boxes that I can't write down and have to do a pretty decent job of remembering since a failed delivery means that I no longer use that drop-point. And none of the locations are just down the street, I have to cover a good distance just to keep from making myself look suspicious; if everything else were free and my time was worth nothing to me, I would still lose money from gas alone if yours was the only package I delivered that day.
TL;DR version: there's a lot more that goes into shipping a package than the amount of postage on it. I didn't even touch on things like hazard cost, though, that's something that vendors should factor into the product cost as it varies from item to item.
Hopefully this cleared things up for some of you.
The Black Hand
Stuff like this makes me appreciate vendors with free shipping that much more.