How do I convince my friend to help pay for something?

Me, my friend, and another friend are trying to make a YouTube account sometime this year. I’m getting all the equipment I need for the videos and one of my friends are helping. However, I have no job, no work permit, and I make $30/week off of chores. It’s too late for a summer job, but my friend already has one and is getting about $1500 over the entire summer. He doesn’t want to invest $300 to help pay for the camera because he thinks we won’t get famous on YouTube. I’ve studied popular youtubers for a while, I’m taking a film class, and I’m self taught on sketch comedy writing.Anyway, how can I convince my friend to help out?