Transcend 512GB SATA III 6GB/S MTS430S 42 Mm M.2 SSD $70.28 @ Amazon AU (via Amazon UK)

This is only a bargain if you happen to require a 42mm Sata based M2 drive for something such as a NUC or laptop that requires SATA specifically.
In my case, it’s the second drive in my NUC11-slim.
2280 and PCIe drives are both cheaper and better, but if you need this – then it’s the best price it’s been in a while.
This drive performs well enough, has DRAM cache and a decent TBW of 280 for its size.