Comment by pabs3

The PinePhone is a cheaper phone supported by mobile Linux distros like postmarketOS, maybe look at that. The CPU is not as fast as the Librem though. postmarketOS has some support for a range of devices though, maybe one of them is cheaper used than the PinePhone for you.

https://pine64.org/devices/pinephone/ https://postmarketos.org/

The PinePhone also has the advantage that the proprietary Linux distro running on the ARM processor within the modem can be replaced with a fully open source distro. I think the Hexagon processor in the modem can't be replaced yet.

https://themodemdistro.com/ https://github.com/the-modem-distro/

See also the Debian Mobile wiki page, which is fairly unmaintained these days.

https://wiki.debian.org/Mobile