

Old thinkpads are the way to go if you want a full libre kernal with coreboot, but I assume you mean foss userspace programs lol
For a desktop look at AMD am4 or higher/6th gen intel cpus or higher, that should enough to get you started (I used a 6th gen intel laptop for 90% of my art, gamedev, and 3d rendering, before I bought a PC and old tablet in 2024). If you got the money for a GPU, go AMD as they have much better support on linux. Even a cheap rx460 is more than enough to make basic 3d games
That kinda rig depending on where you live should run you $400 max. Its enough to get you into the scene and by the time your pushing that hardware to the limit your have enough experience to know what to upgrade
Welcome to the USA: Any improvement thats honest about what it does will be rejected. Instead we will accept obvious lies
Welcome to the USA: YOU are immune to propaganda, anyone who disagrees has fallen for propaganda