There are a number of important events in this great story, but I will try to summarize the key ones.

Greg has always been good at making and saving money. The first important incident is when he forgets his lunch and has to borrow two quarters. The ease with which he is able to borrow this money makes Greg realize that his classmates have quarters to spare, and he starts thinking about ways in which he could earn those quarters.

After realizing that he could get into trouble for selling sweets or toys at school, Greg decides to sell books, which teachers all like. He then launches his own brand of comic books, called Chunky Comics.

The next important incident is when Greg discovers competition. His classmate Maura also starts producing comic books. She starts doing well, and Greg resorts to underhanded business tactics by tearing her book.

Ultimately, both Greg and Maura wind up being banned from selling their books at school. In light of this, they bicker less and less and ultimately start working together instead of in competition with each other.

In the end, the kids strike a deal with the school that they can sell their products in the school store if half the proceeds are donated to the school.