Why must the device be new and still in production? The current devices that are currently in production/new both at that price point (sub 40$) and more expensive (up to 3000$) are consumer grade garbage that will last at most 2 years. They're not repairable, not durable, not built well etc. I personally use a GNU booted Thinkpad X200T /T500 and a GNU booted ASUS KMCA-D8- both running Parabola GNU+Linux-Libre splendisly with the proprietary wifi-card replaced. The cost of the X200T was about 30$ and the T500 was about 20$. I understand that you might not care as much of freedom to get either the X200, X200T, T400, T400s, or T500, but it is important to understand that most of the operating system components you are runnning were made with freedom in mind. If you still don't want to sacrifice performance for a cheap, libre experience, then just get a newer Thinkpad. It's not as libre, but they still could be found (more easily) for very cheap prices. But keep in mind the newer you get the shittier it's going to be. I still suggest the models I reffered to though- esspecially if you want to tinker. You can remove about every component and replace it, and you can replace the BIOS with a fully free bios (GNU Boot).
By the way, most operating system distributions based on Linux as kernel are basically modified versions of the GNU operating system. Richard M Stallman and contributers began developing GNU in 1984, years before Linus Torvalds started to write his kernel. Their goal was to develop a complete free operating system. Of course, they did not develop all the parts themselves—but they led the way. They developed most of the central components, forming the largest single contribution to the whole system. The basic vision was theirs too. In fairness, the GNU project ought to get at least equal mention. https://www.gnu.org/philosophy/philosophy.html https://www.gnu.org/gnu/gnu.html#gnulinux https://www.gnu.org/gnu/gnu-linux-faq.html
https://www.gnu.org/gnu/incorrect-quotation.en.html