Shifter’s Price by Jamie K. Schmidt

In a post-apocalyptic society, sex is currency.

After a meteor destroyed most of the planet, a ragtag group of survivors tries to reform civilization. But this brave new world has new creatures in it as well. Shifters can be any creature they want. Techs can channel electricity out of the air.
Bethany joins up with Lewis and Clark expeditions to travel across the ravaged countryside to find her brother. Lucas, a shifter, has agreed to be her bodyguard and the only thing he has to offer is his body. His sister Lisa is in a similar situation only she haggles with a leather making mistress for the journey. M/F, F/F, M/M and everything in between happen along the way. But there are forces in this dark society that stalk both Shifters, Techs and humans and the team needs to work together to rescue their friends or pay the ultimate price.