HOW MUCH SHOULD I SELL THIS PICTURE?

Hey guys, so I was at the beach taking pictures of a friend when this guy asked me to take a picture of him! I thought this wouldn't work but actually that's a nice picture.

I live in an island and I always see him since I took his picture. He lives on the beach, he gets money collecting cans from people and selling it also asking people for money.

If I sell this picture I would help him, but I don't know where or how come? Can you guys help me? Thank you