Adafruit Micro SD SPI or SDIO Card Breakout Board - 3V ONLY! : ID 4682 : $3.50 : Adafruit Industries, Unique & fun DIY electronics and kits
Connecting Adafruit SD Card Breakout to Leonardo - Instructables
Adafruit 254 Digital MicroSD Card Breakout Board with 2 Gb+ of Storage Works Great with Arduino or 3 v or 5 v Systems: Amazon.co.uk: Computers & Accessories