Well, one thing I did is waiting for a 50% discount, and I did get one and purchased practice set 1-3. You can sign up with them and they'll send you an email of upcoming offers, but it may take sometime. Anyway, to answer your question. Yes, it did help me prepare. In my personal experience, I found that the practice tests (mainly reading section) were a bit harder. For example, in the reading practice, I would score 9 to 10, but it would take me time and I would be disturbed to solve the questions, on the test, I got 12! Listening helps a lot, I highly recommend it.
I don't really know your language skills, but in my opinion, it is kind of worth it, but I wouldn't pay $180 for the whole tests because it's expensive. I also highly suggest the YouTube channel Mad English TV, I also got his book for the writing (it made my life easier).
Hope this helps. Good luck!
