You're right, I take it back. I've become mindful of how expensive a hobby, that sometimes involves dumpster diving, can be when adding up the eBay purchases I've made over the year. They add up FAST and as a result, even $35 USD will make me second guess whether it's something I need or if it is something I could find on AliExpress for $10. But if I were to design and construct such a device, selling at $35 each might hardly be break-even if they're not manufactured in large volumes.
Edit: Just looked at the listing again and realize it says $25, not $35. I misread it when I first looked.