I have a 16yo laptop that runs decently on lightweight linux (arch, openbox on debian) but it will not cut the mustard as a workstation.
There was a “laptop” entry on my gear list so I had my eyes open. I picked up a used Dell E6420 with a small (125GB) SSD for $125 off eBayoff eBay, then ordered 16GB of DDR3 memory off amazon. The E-series ‘tops are highly serviceable; everything is accessible under the back cover. And the E-series is famous for build quality and battery life.
Thinking about dualbooting the Windows 7 that comes on it with either
debian stable + LXQT;
or Antergos/Arch + LXQT
Normally I’d just run Windows in a virtual machine but some things (like firmware updates) work best in native windows.