Don’t You Trust Me? by Patrice Kindl
Morgan is being shipped off to a boarding school for troubled teens and she is not happy about it. While at the airport waiting for her flight, she encounters a crying girl, Janelle, who is being sent to live with her cousin in order to get her away from her older boyfriend. Morgan convinces Janelle to take off with her boyfriend while Morgan uses Janelle’s plane ticket. Once Morgan gets a load of Janelle’s cousin’s house, she decides she should stay and make the most of the situation.
Books about psychopaths often involve murder, but Morgan is not interested in that. She’s a psychopath (or cold one, as she describes it) who just wants to scam as much money as she can from her stolen identity before she rides off into the sunset. Read Don’t You Trust Me? to see if she gets away with it.