Shortages lead to gluts. Get ready.
On commodity markets. GPUs are essentially a monopoly, so gluts are only really possible with outdated hardware.
My favorite eBay listing of today is a lot of 100 NVIDIA P106-100 6GB GPUs for ~$20 each: https://www.ebay.com/itm/305023042595
For those looking for the cheapest higher memory solutions, 24GB P40s are available (decent amount of VRAM, 3X the memory bandwidth, but requires server or DIY cooling, same bad FP16) or IMO the best bang/buck for hobbyists/home devs atm, used RTX 3090s are going for about $600-700 each.
(Note: if you're doing training, unless you have very high utilization/already calculated your costs, you will probably be much better off renting cloud GPUs from Vast.ai, RunPod, etc)
This is not exactly accurate. P106-100 were not specifically made for mining, unlike NVIDIA CMD Hx cards (https://www.nvidia.com/en-us/cmp/). P106-100 cards are NOT artificially throttled, but the specs are still very poor compared to modern cards: https://www.techpowerup.com/gpu-specs/p106-100.c2980
It is true that they are not worth the power costs. I merely made a point that gluts of outdated hardware is a thing even when NVIDIA is a monopoly.
Beyond that, I'm pretty sure that the Techpowerup DB is wrong on the PCIe bandwidth. The first-hand reports I've seen online says the P106's are limited to PCIe 1.1:
* https://www.videogames.ai/2019/01/18/P106-100-GPU-Machine-Le... and 2022 followup on P106-90 https://www.videogames.ai/2022/11/28/Stable-Diffusion-Mining...
* https://www.reddit.com/r/lowendgaming/comments/135fymv/bough...
* https://linustechtips.com/topic/1026742-some-information-abo...
$20 is a fair price for those that actually need exactly what the P106 provides, but the cheeky flipside argument is that having a near monopoly might make even the e-waste overpriced. :)
(Disclaimer: I work for AWS, but opinions are my own.)
(Disclaimer: I used to work there but not on them.)