Kaplan ACT, in particular? From what I gather, these are not practice tests, but just a review / prep.
Abs Dad - I PM’d you.
I used the free Khan Academy practice tests and practice questions along with a Kaplan book for $15 and scored above a 1500- they are not necessary. But if self-study is difficult for some people (like my brother), only then are the classes worth it.
I agree that Khan Academy is a great resource on its own. 100 point jump here.
I would really recommend the Official ACT Online Prep run by ACT itself. It’s much less expensive, and it really helped me (31 to 34). Good luck to your daughter!
@Bella2018 Well, my twins got their ACT scores today. They both scored a 32. Now that the one has decided to NOT try to attend U of Penn, they have great scores for the schools they do want to attend. I don’t know if they should even worry about it at this point. Thank you for your kindness. 
@AbsDad what did they end up using?
@ninakatarina We bought a course from Kaplan, that was $35. They thought it was a waste of time because they said they were reviewing things that they learned in 6th grade… so, essentially, if that was true, they just did it on the classes they have taken… so 32 is pretty awesome…but their SATS were in the low / mid 1400’s if I recall…
One of the things about the ACT math that messed up my kid is that it covers math concepts that he learned long enough ago that he has forgotten them. Reviewing stuff that they learned in the 6th grade might be useful for him and $35 is not that big of an investment. Thank you for your review!