I can understand where you're coming from, but I also feel that I'm in the same boat as well. I know that as a buyer if something is priced way too low I wonder why it is the price it is. When it comes to buying supplies to make my products, I will wonder why some vendors charge less for certain supplies, too. Even when I go out to buy things I need, I'll check and double check the beads I want to buy to make sure they are good quality. I'd rather spend a little more and get a brighter gemstone than get something that looks dull for much less.
On the other hand, I asked for a critique of my store the other day. I don't have many items listed yet and I have more things that I've created and I need to work on preparing those listings. One thing I asked about was pricing. Looking at the products you have in your store I couldn't understand why something similar would go for only 50c or $1. I think you have beautiful items, so prices that low would come as a surprise. Maybe it's just me, but I find it's harder for me to gauge a price on my own work. I think that we're (or maybe it's me) are more critical of ourselves - it's not that I don't take pride in what I make or value my work, but I do have a harder time deciding what I should price my items at. Some of the feedback I received in my critique was that my items were under priced. For me, that came as a surprise. I was worried about what a good price range was and I think it's a lot easier for an outside eye to look at what you've created and tell you as a buyer what they would spend. Again, that could just be the way I see it. I wouldn't price my items at 50c because it wouldn't even cover the COGS, but I sometimes hesitate in raising my prices.
It does make me wonder why some people do it, though. As someone else mentioned, the required wage to live in some places may be much less than where you or I are, though you did say the shop was of a US seller. I know I saw an international shop selling necklaces, mostly just pendants on a chain, for just a few dollars each with shipping. They have a ton of sales and lots of feedback, but I wondered the same thing. How are they able to cover the cost of their materials and shipping to keep their shop running?