Adata via Amazon offers the Adata Ultimate SU800 M.2 2280 512GB 3D NAND Internal SSD for $112.99 with free shipping. That's the lowest price we could find by $42. It features read speeds of up to 560MB/s and write speeds up to 520MB/s.

Note: Adata via Amazon also offers the Adata Ultimate SU800 512GB 3D NAND 2.5" Serial ATA 6Gb/s Internal Solid State Drive for $109.99 $108.99 with free shipping.