What ThinkPad/Latitude models are cheap and usable right now? I'm just looking for something to browse the web, but not something so low-spec that it couldn't handle heavier desktop environments.
Check out Minifree Ltd. They refurbish old Thinkpads, replace the bootloader with libreboot, and come with encrypted Debian KDE. They offer either the T440p or the X230, and you can choose different SSD and RAM configurations. Prices are as low as £258.00 for the X230 with 16GB of RAM and a 480 GB SSD.
Minifree is between double to triple the price of the same laptop on eBay. Libreboot is strictly an ideological matter, it doesn't help with privacy if software installed isn't configured a certain way and also what software is installed.
BIOS is not the bacldoor is. Also, if you don't build your on router, you can't garauntee who your router is sending packets to. Also DNS makes a different. Libreboot does not provide the protection think it does.
It doesn't help that Libreboot laptops are at least 10 years old. Those are some low resolution LCD screens compared the LED and full hi-def.