B&H Photo-Video offers the Crucial MX100 Series 512GB Serial ATA 6Gb/s 2.5" SSD, model no. CT512MX100SSD1, for $199 with free shipping. (Amazon offers it for a buck more for the same price.) That's a buck under our mention from four days ago and the lowest total price we could find by $13. It features a 9.5mm adapter, read speeds of up to 550MB/s, and write speeds of up to 500MB/s.

Update: Note that Amazon now charges the same price.