As of now, Angel Station by Walter Jon Williams can be downloaded from Amazon (US, ES) for only $0.99. This is the synopsis of the novel:
ORPHANS OF DEEP SPACE . . .
They’re outlaws now. Created to serve a function grown obsolete, haunted by the holographic ghost of their father, Ubu and Maria have lived their entire lives skating along the edge of extinction. Now they and their ship Runaway are in flight both from the law and from a predatory clan of competitors. They’re going to come back rich, or not at all.
But what they find in the depths of space isn’t wealth, but a secret so startling that Ubu and Maria will need every last reserve of guile, cunning, and intelligence just to survive . . .