If you like the Freeground, the The First Light Chronicles Omnibus (which contains all three books: Freeground, Limbo, and Starfree Port), is currently available for the Kindle for $9.99 or as a print version at $17.99. This omnibus version of the trilogy is more cost effective than buying the second two as standalone books (plus it puts Amazon in charge of backing up your bookshelf, if you have a Kindle).
His Spinward Fringe series follows the First Light Chronicles, and is an unlimited series (it's recommended that you read the First Light Chronicles first) and is also available at Amazon in trade paperback or Kindle versions. So far, the titles available are Resurrection, Awakening and Triton
Synopsis:
In the middle of the darkest region of explored space sits one bright beacon; Freeground Station. Serving as a supply and trading post it is home to a select number of human beings that will take an unlikely chance to make a difference in their end of the galaxy.
Jonas and his friends spent their spare time in tactical simulations and drew the attention of Freeground Fleet Command when they hacked into restricted combat scenarios for elite trainees and defeated all comers.
Instead of punishing Jonas and his friends they offered them an opportunity to undertake a dangerous and exciting mission. They were to go out into the Galaxy and acquire any advantages that would improve life for Freegrounders.
This series is about their first voyage together, the challenges they face, and the relationships they forge with each other and the beings they meet along the way.