Most sites offering a free are usually one of two things:
It highlights kanji that look alike or have similar meanings to help students avoid common pitfalls on the exam. Study Recommendations and Resources
The final day of each week is dedicated to a review test modeled after actual JLPT questions to track progress. Visual Aids:
The is a highly popular 8-week study guide designed to help you master 739 kanji and approximately 1,200 vocabulary words for the JLPT N2 exam. Official & Purchase Options