Most companies are different on first steps. Some want you to complete tests the moment you apply, some invite you later on for online tests and some have no online tests.
If I were you I’d hold off buying software for testing until you’re fairly certain you’ll be invited to actually sit the psychometrics. You need to pass the sift to get to that stage (company selecting who to pick progresses) and this stage is notoriously hard to get past as you need both luck and a good application. You could be 1 of 5,000 applications at that stage, and they may only have 10 jobs available.
What they look for at the start? You to be in a position where you can already demonstrate the qualities they want in a driver. They love applications from people in safety critical roles (emergency services, military, medicine) to give you an idea of the types they like. So your application needs to show that your background is already heavily within dangerous working environments, process driven environments and regulated environments.
If you’re invited to psychometric testing you’re given enough notice to be able to practise (I think 7 days?) and that should be ample if you buy the software - remember, many, many, many buy the software and still fail thought. The tests are designed to test your core ability as a human and are quite hard to fool with fake skill potentially gained from practise material - basically, you either have it or you don’t, most don’t.