The aptitude tests are there to see if you are up to the challenge (and yes I have done the box one you are talking about). You are about to spend a lot of money on your training. Sure you can use online apps/sims to boost your score and scrape a pass. But is that going to help you pass your IR? What about your sim check for an airline?
I would just warn you to have a serious think before you try to improve your score; is it REALLY helping you long term...? Sure some people go on to have great careers after practising, but other do not! Failing might feel awful but it could also be doing you a huge finicial favour long term. But best of luck with your choice