Money Doesn't Grow on Mars: Self-Control — Lori Haskins Houran

Acting like an Earthling isn't easy! Follow the adventures of Spork the alien in the How to Be an Earthling series. Each book covers a different character trait to help kids think about what they say and do. 
 
Making money is easy! Jack gets two dollars to sweep the sidewalk, a dollar to take out recycling, five dollars to dust. Soon he'll have enough to buy a special issue of his favorite comic book! Jack has it all under control, unlike Spork, who's crazy for video games. But Jack forgot one thing. Making money may be easy. Keeping it is hard! Every How to Be an Earthling title includes fun back-of-book activities that build on story themes. (Character trait: Self-discipline)