Amazon has the Transcend 128GB JetDrive Lite 350 Storage Expansion Card for 15-Inch MacBook Pro with Retina Display, model no. TS128GJDL350, for $54.99 (69.99 – 21% instant savings) with Free Shipping for a limited time.

The Transcend’s JetDrive Lite 350 Expansion Card gives you the chance to instantly boost the total available capacity of your MacBook Pro system without the need to upgrade to a larger capacity SSD. It’s specifically designed to fit neatly into the card slot of the 15-Inch MacBook Pro with Retina Display and features a max read speed of 95MB/s and a max write speed of 60MB/s.