Interesting thread here that slipped past me. From my recent thread, it seems calculating at minimum wage and adding material costs doesn't always work, but it depends on the items and who is buying them.
I can make a good hourly rate making custom leather products for motorcycles, but I don't seem to get the same return on bush crafty stuff and sometimes it isn't even worth while making an item.
Sheaths are a great example. I've just finished making a custom sheath for a knife for a friend of a friend, which when I add it up in hours really wasn't worth my while. it takes time to properly fit and finish a custom sheath, but when people can buy a chinese made knife with a sheath made in a sweat shop for less than it costs you just to make the sheath, it gets difficult to make any money at all.
It's a shame that we have become so used to mass produced, imported items that are built on the exploitation of others, but that's the sad reality. In the last few years I have tried as much as possible to only buy items that are responsibly sourced, but it is difficult for that very reason.