If you bought a BBB you will need at least one microSD card to burn the image on. Here is about the best deal around -

http://www.amazon.com/SanDisk-MicroSDHC-Frustration-Free-Packaging--SDSDQU-016G-AFFP-A/dp/B009QZH7D8/ref=sr_1_3?ie=UTF8&qid=1399086981&sr=8-3&keywords=sandisk+microsd

Highly recommended is at least Sandisk ultra 16G  class 10 30mb read.

Buy at least three for free shipping.

73 Doug
WA3DSP
http://www.crompton.com/hamradio