You're sadly not wrong. I've seen the financials of selling bikinis. $2.5 product + $9 shipping + $20 in facebook ads => sold for $75 As for supermarkets, the

You're sadly not wrong. I've seen the financials of selling bikinis. $2.5 product + $9 shipping + $20 in facebook ads => sold for $75 As for supermarkets, the main difference is probably what they charge you for placement. If you (the manufacturer) want your product inside a supermarket, you typically have to rent the shelf space from them. And depending on where inside the shop that shelf space is located, it'll be priced vastly differently. That is also one of the reasons why you typically only see high-throughput high-margin products close to the cashier, e.g. sugar candy for kids. But I feel like on the electronics side, it's not that obvious. When you need access to electronic components, being close to the markets in Shenzhen is a huge advantage. Shenzhen engineers can just walk over, chat to the manufacturer, and buy some sample products. Western engineers need to read the spec sheets and then wait 2 weeks for the samples to make it through shipping and import clearance. Also, some top-notch components only have descriptions in Chinese, because the manufacturer knows that 99% of their market is selling to other Chinese companies, so they don't bother producing an English datasheet. The result is that Shenzhen shops are not only cheap, but also better quality.