Hi Alan, I took the IAPM exam this saturday and got my provisional feedback right after. It said "Likely to Pass" which I am very happy about as it is accurate almost every time. I gave myself a month from the exam to start studying, but since I also work full time, I was only really able to study on weekends (I'd say a total of 10-15 hours a week).
The LAREPrep guide really helped me a ton. I read over the study guide and wrote bullet points down for myself (personally I retain more information when I write them down). After I finished the study guide, I bought both of the LAREPRep practice exams for section 1 and took them a bunch of times, studied the questions + answers each time, until I got everything right or very little mistakes. I then bought the CLARB practice exam and took it 3 times (the max you can take it). Reason why I bought the LAREPrep practice exams first is because you can take them multiple times, so you can do so until you retain all the information from those practice tests.
If you're trying to not spend too much, I'd say 1 LAREPrep practice test and the CLARB practice test would suffice, or even just the CLARB one would do, but I think the study guide is ESSENTIAL.