I'm in the market for a Linux friendly ultralight laptop to check web apps and run terminal, nothing fancier then that. Do any cheap systems exits these days? I was looking at a chrome book but apparently the mediatek chip doesn't play nicely with FOSS.
What about something like the Thinkpad X201? It's not ultralight but it is quite small.
Other than that I'd probably say a Chromebook with a Linux install. Second hand they are quite cheap and can likely do what you are after. A lot of them have passive cooling which is nice for a couch device. I was able to install libreboot on my C201P quite easily and now it just runs a traditional Linux install
I'm writing this on my x201 on my couch. I love it, but it's not a great couch laptop. It's kind of heavy, runs hot, and has poor battery life vs more-recent comparables.
I used to have X230 as a daily driver for laptop (I got separate desktop) and it's a really nice machine for it's size. Only the display is a bit lacking by todays standards as it's only 1368x768, but for 150€ (give or take) it's not too bad.
I prefer the T480 series (imo Thinkpad went downhill from there onwards). The non-s is a great off-road laptop, but for what OP is asking, the T480s seems like a more sensible choice.