Teaching martial arts is a gift for your student(s) and you. For me, teaching helps me troubleshoot my own techniques / understanding of the techniques; but I find that I also learn more by "sharing". When I verbalize a technique or flow, compared to just "training it" - it forms other pathways in my brain the give me a higher understanding.
In regards to paying, it's your first "student". When I started my first "school" years ago, I was training at a Kyokushin Karate place, and started teaching Jiu-Jitsu to a fellow student who wanted to learn the grappling arts. I didn't charge him, it was a passion project. But what ended up happening was that other students became interested as well. Soon, 1 became 2, became 5, became 10, became 150+.
You never know where this training can lead. It may just be you helping a kid who needs it. You're changing his life and inspiring him to be better. That in itself, is an amazing thing. Next thing you know, he's telling his friends, and next thing you know, you can start a new business for yourself.
So - I would suggest share you passion, and let it go from there.
Oss.