Just a quick, comical summary of my experience trying to get a GPU since just prior to the launch of the Ampere cards.
I work in film post production and I have no prior deep learning coding experience, but I wanted a GPU with a lot of memory to process high res imagery with an existing TensorFlow-based open source toolset that I could just about figure out how to use with my small amount of Python experience. I did secure a Titan RTX off Amazon(!) at retail price, but I decided to return it when I found out about the imminent release of the Ampere cards because $1500 sounded a lot better than $2500.
Of course, the 3090 is going for around the same price as the 2.5k rrp I paid for the RTX Titan. I was very naive at that exact moment about the fact that crypto mining was going to go back into full swing, although I was warned by someone on this very sub. I did expect Eth proof of stake to cancel some of that out, but we aren't there yet.
Besides availability issues, there was also the size of the 3090 which Nvidia seem to have intentionaly made huge so it can't fit in a typical deep learning rig or graphics workstation. No problem, I'll get a third party blower card – if I can find one in stock. Whoops, now Nvidia killed them all!
Alright, now I'll look at one of those rinky-dink third party RGB gamer cards that are sufficiently low profile – I only need one card with 24GB VRAM. Okay, they are all sold out forever and if you can get one, it may be as expensive as the previous Titan.
So maybe it's best to get an A5000 or A6000, because tbh it seems they are more likely to go for RRP which makes them not a huge step up from the inflated 3090 prices and they are better supported on Linux IMO.
I have just found out about the LHR cards though, that will be shipping soon. But also that there may not be a 3090 LHR, so it doesn't seem like supply will necessarily improve.
There is now a proprietary GUI-based toolset by the same developers which is now using PyTorch as the back end. But it's still recommended that 24GB is where you really want to be at memory-wise without needing to slice up the input images too much, so this issue is not going anywhere. I had managed to get a 2060 Super with 8GB as an interim card which is really the bare minimum. It's also comical how much those cards are going for now, so I'm glad I snagged one of the last ones at Best Buy for $400 RRP last year.