IMHO

and

It didn't take me long to figure out that by the time I prepared and stored, scanned, listed, filled an order, prepared the mailing, went to the Post Office, etc. I was making about -$23 an hour for my effort when selling low value items.
I'm all about working in the negative (value wise) with my collection, but not with my time doing all that.
That said, if you're enjoying the effort then go for it. I don't think you've listed the US too high but I don't know about the others.