Star Soldier by Vaughn Heppner is 99 cents in the Amazon Kindle store, and has received an average user rating of 4 out of 5 stars based on 106 customer reviews; you can check it out by clicking here or typing in http://amzn.to/k4h9M0 into your computer’s web browser.
Here is the book’s description from the Amazon website:
It’s survival of the fittest in a brutal war of extinction!
Created in the gene labs as super soldiers, the Highborn decide to replace the obsolete Homo sapiens. They pirate the Doom Stars and capture the Sun Works Ring around Mercury. Now they rain asteroids, orbital fighters and nine-foot drop troops onto Earth in a relentless tide of conquest.
Marten Kluge is on the receiving end. Hounded by Thought Police, he lives like an ant in a kilometer-deep city. The invasion frees him from a re-education camp but lands him in the military, fighting for the wrong side.