Steam Machines are popping up on reseller sites and successfully selling at crazy markups, with some units going for double the standard price or more. While scalping isn't uncommon, none of these sellers actually have a Steam Machine in hand, as it hasn't yet been sold by Valve.
Steam Machines will likely be in short supply, which likely helps drive these listings and sales. Valve noted that it was only able to produce about two-thirds of the amount it wanted to make available due to the parts shortage that is plaguing the industry right now. With Steam Decks often sold out upon launch before the AI hardware crisis looms, the availability of Steam Machines is likely to be even worse.

Valve explains why the price of the Steam Engine is so high
Valve officially explains why the Steam Machine is so much more expensive than typical game consoles and how the demand for parts has affected the price.
Steam engines are scalped before they are even secured
Steam Machine listings are popping up on eBay, with many priced at $1,000 or more over the cost of buying directly from Valve. Although there are still many, a few have already sold. For example, one listing for the cheapest Steam Machine was selling for $2,000, which would normally sell for $1,049 direct from Valve. A pair of 2TB Steam Machines sold for $2,700 and $2,900, respectively, while normally costing $1,349 on their own or $1,428 with a controller. Perhaps the most stunning price is a 512GB Steam Machine with controller that sold for $2,800 on eBay, which would normally cost $1,128.
Select the wrapper to complete the equations.
Start

Select the wrapper to complete the equations.
Easy (15s) Medium (10s) Hard (5s)
However, the most shocking thing about the sales is that none of the sellers have bought yet, as the sale with Valve has not officially started. Instead, these sellers only have emails confirming they've been selected for purchase once the consoles actually go on sale. It's clear that some Valve fans are willing to spend exorbitant sums to get their hands on the console, though many balked at even the systems' standard prices.
Valve has shared why the Steam Machine is as expensive as it is, explaining that it doesn't subsidize the Steam Machine like the big console manufacturers sometimes do. Interestingly, this seems to be a change in the way the Steam Deck was handled, as Valve CEO Gabe Newell noted that the Deck's pricing was “very aggressive” and “painful.” However, it had to compete with the Nintendo Switch, which is one of the most popular gaming consoles of all time.
At this point, it remains to be seen how the future will play out for the Steam Machine and those hoping to purchase one. Some have become wary of the system, especially after Valve quietly changed details regarding the Steam Machine's 4K and FPS capabilities. However, if the system lives up to the hype, even more players may want to buy it. However, with the AI boom leading to severe parts shortages worldwide, Valve could potentially struggle to meet demand in the coming years. It's ultimately up to players who didn't get in line to decide if they want to try and wait or spend a lot more than MSRP to secure one.