I would suggest saving your money and studying on your own. My friend and I both performed similarly in Organic Chemistry, and my friend went with a prep company and I decided to study on my own for the MCAT. He scored a 515 and I was able to score a 522. I am sure we both worked equally hard, but I think the difference comes from being able to control your study and being able to use the best resources. Test prep companies will train you using their resources, which includes very few of the official AAMC practice problems (problems written by the people who wrote the MCAT!). During my study I found test prep companies' practice exams and practice questions to be subpar. I feel like they take you off track more than help you. I would suggest making a study plan that uses various resources (AAMC, Khan, Kaplan, Princeton, ExamKrakers). Variety is your friend.
Lastly, I enjoyed studying on my own because I was able to make the plan that worked for me. I was able to study from home and study only as much as I could each week (very helpful since I was still taking classes during my exam prep). Best of luck with your preparation!