I personally did not subscribe to any app or did not want to pay for anything. I read the discover canada booklet 3 times, I took some notes in an excel to organise the important dates to make sense of the actual flow of events. Additionally, gave some practice tests from Richmond Library. On the day of the exam, I just did the 150+ questions on Richmond library and made sure I get above 90%, because those tests are slightly difficult compared to the actual test. The actual test was a breeze, I think I took around 7 - 9 mins with a score of 20/20