There are a number of free resources for your FITREP/Eval and Award writing. Before spending money on any FITREP or Evaluation writing guide review the instructions below.
SECNAVINST 5216.5 – Navy Correspondence Manual
SECNAVINST 1650.1H – Navy and Marine Corps Award Manual
BUPERSINST 1610.10 – Navy Performance Evaluation and Counseling System
US Navy Style Guide – Created by the US Navy Office of Information