I really liked the first few free practice tests and it worked perfectly so I paid $10.99 for all 200 lessons, which seemed pretty steep. Despite overpaying, the app repeatedly prompts for a 5 star review it says will remove the ad. Giving one doesn't remove the ad and it doesn't stop the prompting. You can bypass this annoyance by just hitting SKIP up in the top right corner, and then SPACE for the test to finish. The app itself is awesome and would be worth 5 stars if it weren't for the disruptions, the intrusive ad, the dishonesty about removal and the fact that it even still has an ad after paying over $10.00 for it.