I never paid for any myself. I saw that sumo has free ones too.
Honestly, Cali Lessons should be your best friend right now. They might get the rep of being over rated, but they spoon feed it to you and then test it to you as well. Stick with those untill you got it down. If you don't get 100% on Cali, you are wasting money going anywhere else untill you do.
Also, can you get ahold of your Profs old exams and answer keys?