Dark Horse Comics is currently holding a flash sale in its digital store, featuring the comic entries in the Mass Effect catalog. Single issues are going for $.99, while the bundles are going for at least half off (the Homeworlds bundle in particular is a great deal). You can also get The Art of the Mass Effect Universe in digital format on sale as well.
Furthermore, the one-off Blasto: Eternity is Forever issue is free for any digital store account-holder. Of course, while
absolutely not necessarily canon, it's still a entertaining read.