Michelle Diener's
Breakaway (Verdant String #1) is $.99. While it is the first one and stands by itself, I think it'll make more sense if you read the prequel novellas
Interference & Insurgency first.
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Spoiler:
Sofie lives in the shadow of Felicitos--the tethered way station built to funnel Garmen's mineral wealth to the top of the atmosphere to be traded. Because Garmen is a breakaway planet, not part of the Verdant String Coalition, the companies that control it are free to run things as they see fit, and Sofie is part of the resistance that wants to end their rule.
What she really wants, though, is to get away from Garmen altogether, and leave the drudgery and violence behind her. But when she meets Leo Gaudier, a shadowy crime lord who she admires for his ability to cheat the companies that own Garmen, her goals become less clear--and when she stumbles on a terrible new direction the companies are taking, she struggles with whether she should stay and fight, or run away.
Leo is all too aware he doesn't know enough about Sofie, something his own security detail is not slow to point out, but he can't keep away. When Sofie reveals her links to the resistance, and shows him those in control of Garmen have begun swimming in dangerous waters, he realizes his plan to overthrown them in a careful operation of a thousand cuts is no longer workable.
The time has come for a single, lethal strike--and that will not be without consequences . . .