Amazon offers the Toshiba 256GB Serial ATA III 6G/bps Internal SSD Kit, model no. HDTS225XZSWA, for $149.99 with free shipping. That's the lowest total in-stock price we could find by $30. It features read speeds of up to 552MB/s and write speeds of up to 501MB/s. The upgrade kit includes a USB to SATA conversion cable, SATA signal cable, SATA power cable, bracket, and screws.

Of note, it is currently on backorder with an estimated ship date of one to two months.