If you're looking to get an RTX 4090, we've found two deals on entire gaming PCs for not much more cash

pcgamer.com:

HP OMEN 45L | RTX 4090 | Ryzen 9 7900X | 2TB SSD | 64GB DDR5 | $3,699$3,299 at B&H Photo (save $400)
This is a genuinely powerful top of the line gaming PC for not much more money than you'd spend on an RTX 4090 on it's own. With a spec sheet that makes most games tremble in its presence and a dominating sheer black chassis, this is a serious machine with serious credentials.

Skytech Eclipse | RTX 4090 | Ryzen 9 7900X | 1TB SSD | 32GB DDR5 | $3,899.99$3,199.99 at Newegg (save $700)
Mega specs for not entirely mega money here. While you might want to upgrade the storage capacity to something chunkier for all those big game installs and that all-white chassis isn't for everyone, there's no denying that this is a huge amount of performance for this price, and from a builder with a good reputation too.

While it's true that the price of GPUs on the whole is still rather high, it's the RTX 4090 that has really seen its pricing shoot straight up into the stratosphere in recent months. A quick hunt through the listings reveals that a lot of examples are currently priced well north of the $2,000 mark, with some coming close to $3,000. That's a huge chunk of change for a single component, but above we've found two entire gaming PCs for not that much more money.

First up, let's take a look at the HP Omen 45L GT22-1190. Not a particularly memorable name we'll grant you, but this is an honest-to-goodness powerhouse of a system from a reputable manufacturer, and given it's currently available for just under $3,300 the pricing here is very much on point. It's not like HP skimped on the rest of the spec sheet to get it down to this sort of money either, as alongside that RTX 4090 comes a 4.7 GHz AMD Ryzen 9 7900X, 64GB of 5200 MHz DDR5