Unless you were literally born yesterday, you probably remember a time when PCIe NVMe SSDs cost $300 or more for a 500GB drive. Even now, you normally have to spend well over $100 for a reputable PCIe NVMe drive with that capacity.
However, today, the HP EX900 500GB SSD (opens in new tab) is a great $74.99, if you purchase it from Newegg's eBay channel. It was $63 yesterday when you could get 15 percent off all eBay purchases, but this is still a great price.
However, you might prefer the stronger performance of Intel's 660p, which is also $74.99 in the 512GB (opens in new tab) capacity on Newegg right now. The 2TB Intel drive is just $249.99 (opens in new tab).
When we reviewed the HP EX900 last spring, we gave the drive high marks for its solid performance, but noted that its lack of on-board DRAM prevents it from being one of the fastest. Still, the drive is rated for a strong 120,000 random read IOPS and 108,000 random write IOPS along with a 2,100MBps read speed and a 1,500MBps write speed. That's way faster than a typical SATA drive.
Note that the HP EX900 is in the M.2 form factor so your PC will need to have an open M.2 slot to accommodate it.