I got one from Amazon. A 32-thread Ryzen 9 7945HX, along with a motherboard, CPU cooler, case, and PSU for $400. But I didn't trust the PSU, so I bought a better one, replaced the thermal paste with PTM 7950, and replaced the CPU fan with a Noctua.

I also had to buy SODIMM DDR5 RAM modules (just before prices skyrocketed, I got 64 GB for $180), a 2 TB Samsung NVMe SSD, and an RTX 5060. The CPU comes with an integrated GPU, but I disabled it to get better cooling.

I also wanted to replace the CPU cooler with a Noctua one, but the GPU sits too close to the CPU. Maybe someday I'll adapt a liquid-cooling radiator, but that would require 3D printing a custom adapter and making multiple trips to a 3D printing shop for trial and error. That's too much hassle.