If you think finding a needle in haystack is difficult, try buying a standalone GeForce RTX 30 series graphics card from a first-party seller, at (or close to) MSRP. It's an almost impossible mission. Finding one as part of a prebuilt PC is marginally easier, and if you're willing to go that route, Best Buy is selling a well-rounded CyberPowerPC Gamer Supreme with an Nvidia GeForce RTX 3070 for $1,549.99.
Best Buy offers several other desktops with the latest graphics cards based on Ampere, though they are usually out of stock. In fact, this is the only one that is available at the time of this writing—and it is not likely to stay that way.
CyberPowerPC Gamer Supreme | Ryzen 7 3700X | GeForce RTX 3070 | 16GB RAM | 1TB SSD | $1,549.99 at Best Buy
At the time of this writing, this is the only prebuilt desktop with a GeForce RTX 30 series graphics card that is in stock at Best Buy. It's a good build from top to bottom, too.View Deal
Overall, this is a good system for the money. It pairs the RTX 3070 with an 8-core/16-thread AMD Ryzen 7 3700X processor, which is a last-gen part (Zen 2), but still plenty fast for gaming. It's also stuffed with 16GB of DDR4-3000 RAM and a 1TB SSD, leaving little to quibble about with regards to the core specs.
Other notable features include an all-in-one liquid cooler, RGB fans, and what multiple user reviews say is an 800W power supply with 80 Plus Gold certification. It comes bundled with a keyboard and mouse as well, which if nothing else, you can toss aside as a backup in favor of better peripherals.