I've actually done this, signup to monetize your youtube videos, signup for Google Adsense, become a member of the Amazon Affiliate program and find products to push. Find affiliate programs for gyms (yes they exist). I went as far as to create a weekly podcast to talk about my struggles, answer questions from my user base (first month I faked the questions but the end result was achieved) Its a great way to build engagement and thats where most of your efforts needs to go towards. The more personal, or connected they feel to you the higher the reward.

Those are just as few things I started out with, I'd be happy to go over how I created my vlog and sold it with you anytime.