Free mentorship is great and you can find that in many brokerages. Just realize what free might mean. It might mean help when ever the mentor has time. It may not be a consistent thing. I'm going to use KW in my example as I have always been a KW associate and I don't know other franchise's systems. I don't push KW because it isn't for everyone.
KW has a lot of training via their website. You could learn a lot from the free training there. Looking back, I wish I could have had some consistent mentorship. You learn a lot in school, but you usually don't learn the little tricks of contract construction to protect your clients. You learn scripts on the internet to do a listing presentation, but it is wonderful to be able to sit and listen to an expert in action to handle objections. Our newbies here have a hard time because of lack of consistent volunteer mentorship.
What I'm trying to say, is if you can afford it, don't discount the paid mentorship. It sounds like bargain at only 10-15% (I've heard much higher!!) The mentors have reason to help you succeed. Just make sure at the start you agree to the obligations you both have for time spent in training.
Good Luck!