The book "Lunch Money" has one main protagonist, Greg. For most of the story he is a 6th grade student, and he is a fierce entrepreneur. The kid knows how to make money, and he works hard at it. His 6th grade money making plan is to make and sell comic books to students at school. From here, Greg runs into a few different conflicts.
Greg's first conflict is with Maura, who also begins to sell comic books of her own. She has a nasty habit of taking Greg's ideas and improving them. Greg doesn't enjoy the competition. Their rivalry comes to a violent head when Maura hits Greg in the face. It ends up working out okay, because their teacher, Mr. Z, helps them work through their conflict. After that, Greg and Maura agree to begin working together to operate a comic book business together.
The next conflict follows shortly after. Mrs. Davenport, the school principal, makes a rule that students will no longer be allowed to sell stuff to other students at school. Maura and Greg are obviously upset, because a fairly big roadblock has been put in their way. Together they notice that the school does allow the selling of books to students, though. The school committee allows the book club to sell books to students. Greg and Maura go before the school committee and petition that they, too, be allowed to sell their comics at school. As part of the deal, they say that a portion of their profits will be donated to the school library. The school committee likes the idea and agrees to let Greg and Maura continue their business.
By the end of the school year, Greg and Maura have become good business partners with each other. They have inspired other schools in the area to do similar student projects. The school library got a nice donation at the end of the year, and Greg has learned that it feels as good to donate money as it does to earn it.