There are some, but a lot of them have very spotty Linux support. In most cases either you're stuck with some ancient kernel provided by the manufacturer, or you're relying on community support from Armbian at best.
Take for example the OrangePi Zero 3[1], which you can get[2] from around $25.
Armbian provides community support status[3], so you're relying on volunteer efforts to provide updates and support. Also drivers for peripheral devices might be missing[4].
There are others, like say the NanoPi Zero2[5][6] for around $20, but again, support might vary. The Zero2 is so new it's not listed on Armbian, and most of the other NanoPi's are under community support.
That said, I've been running some NanoPi ZeroPi's (the Zero2's predecessor) for several years now, without any issues. Just using them for light loads, one is my PiHole for example, but yeah can work great as long as you do a bit of research in terms of what's supported and not.
[1]: https://www.cnx-software.com/2023/07/03/orange-pi-zero-3-all...
[2]: https://www.aliexpress.com/item/1005007673457198.html
[3]: https://www.armbian.com/orange-pi-zero-3/
[4]: https://linux-sunxi.org/H616
[5]: https://www.cnx-software.com/2024/09/13/nanopi-zero2-tiny-he...
[6]: https://www.friendlyelec.com/index.php?route=product/product...