The Walton Street Tycoons was suggested for the Prometheus award, but I don't think it will be a serious candidate. That's not because it's not libertarian enough, though, it's because it's completely not science fiction. Even 47 had more sf than this. The story tells of the spontaneous creation of a thriving market among a bunch of seventh graders in a small town that has fallen on tough times. All the kids get into it, and their problems with competition and government interference are quite entertaining. But the main character doesn't think like a 12 year-old, he thinks like an experienced, mature 27-year old. His sex drive, understanding of women, ability to organize, and expectations of his parents and teachers are much more suited to someone who has already been in the working world for 10 years than to someone who is discovering it all for the first time.'s
The story and the characters are unrealistic enough that I wouldn't recommend it to non-libertarians and the aspersions cast at school, liberals, and government officials would make it hard for any of them to get through. Especially since the aspersions come from the mouths of 12 and 13 year olds in contrived and implausible situations. For libertarians, the situations are merely mild exaggerations of the kind of shenanigans we expect from government agents, but to less sympathetic eyes, they'll look contrived and out of the ordinary. This is not the best way to convince someone that government doesn't work the way they think.
For libertarians, this is a mild diversion. As outreach, it's polemic and unbelievable.