Yes and no. I'm comfortable with Jawa, not with FB. Never used Offerup. Problem is I'm not seeing 40 series available on used market yet. The few 40 series that are left in stock brand new are still astronomically priced. Why would I spend that on a 40 series when I can (eventually) get 50 series for same price?
I also have a specific target - nothing less than 4080 Super, performance-wise. I plan on a custom water-cooled loop, which means I have to factor in waterblock availability as well. I've got my eye on a Gigabyte 5080 Waterforce that has the block preinstalled, but I've already seen the prices going up, even though it can't be found anywhere.
My ideal wish is to find (eventually) a used 4090 for $1400 or less. Right now that's a pipe dream