So, on July 29, 2015, Aliens in the Soda Machine and Other Strange Tales period of enrollment in kdp select ended, which means it is no longer available as a free read through Kindle Unlimited, alas.
However, as it moves its story-laden spaceship over to Smashwords, it can be had there for $1 as a pre-order until August 31. (It becomes available through Smashwords distribution August 30.)
Use this code: EF37D
At this link: https://www.smashwords.com/books/view/527815
And of course, enjoy the song: