It wasn’t until my first college finance class that I started to learn a little bit about investing and how the stock market works. Then it wasn’t until my 30s that I implemented some of that knowledge, and added to it, to create a strategy for investing our resources into different companies and ventures.
Now, as parents, we want to give our kids a leg up on where we were at their age and give them the tools that they need to have a basic (and preferably an intermediate) level of knowledge about how different types of investments work. And specifically, how investing in the stock market works.
Here are some resources that you can use for FREE to help your kids have a working knowledge of how the stock market works (click on each title to go directly to the website):
Join a game and get $100,000 in virtual cash to invest. Pick stocks, ETFs, and cryptos to create your virtual portfolio. Track your performance on the leaderboard! Wealthbase  also have a learning center to learn about investing and financial planning strategies to help you build and preserve wealth.
An online simulation of the global capital markets that engages students grades 4-12 in the world of economics, investing and personal finance and that has prepared nearly 20 million students for financially independent futures.
Parents will need to register with the website  to create a profile.
Start with $100,000 in virtual cash and put your trading skills to the test! Compete with thousands of Investopedia  traders and trade your way to the top. Join or create challenges with your friends and other investors. Compete to see who has the best investment results daily.
HowTheMarketWorks  is a FREE stock market game that allows users to create their own custom stock game and create educational lessons for their players. It is used by over 400,000 individuals and students each year. Users register for free and receive a virtual $100,000 and access to our Education Center. Users can then create their own custom stock market contest and invite their classmates, friends, family or co-workers to a friendly competition.
Market Watch 
If you already have a basic knowledge of how the stock market works and want to put your skills to the test, check out Market Watch! Build your portfolio and react to the markets in real time. Compete against your friends or coworkers to earn your spot at the top of the leaderboards. Market Watch  allows you to do virtual advanced trading (like limit and stop loss orders, partial shares, short selling, margin trading, and more!)
We love lots of the Khan Academy courses ! They are completely free and on the topic of stocks and investments they have videos on all the following:
Introduction to stocks
Understanding company statements and capital structure
Corporate metrics and valuation
Life of a company–from birth to death
Mergers and acquisitions
Mutual Funds and ETFs
There are several great video options at the link above for a variety of ages and learning styles.
BusyKid App 
It’s not free, but there’s an app called BusyKid App that costs $19.99 per year and allows you to give your kids their allowance through the app. They can spend their money through a (provided) pre-paid debit card and they have the option to use part of their allowance to invest in the stock market and watch their money potentially grow if they invest well.
There are also several books to either check out from your local library or purchase!
Go! Stock! Go! 
Go! Stock! Go!  employs a cartoon-like “Dr. Seuss” style as it becomes the first truly user friendly book on stock and finance.
A storybook follows the Johnson family as they learn the fundamentals of stocks and bonds, the mechanics of investing, and important lessons on risk and reward. The humorous illustrated story is simple enough for children and teenagers yet is also directed towards adults and kids of all ages.
The book offers an advanced section “Let’s Talk Stock” that provides an added level of knowledge for older readers. While designed with children in mind, this book is sure to become an adult favorite.
Budding tycoons and those with more worldly concerns will appreciate The Motley Fool Investment Guide for Teens: 8 Steps to Having More Money than Your Parents Ever Dreamed Of  by David and Tom Gardner with Selena Maranjian. The editors of the Motley Fool Web site offer sound advice on everything from finding a job, investing in the stock market and avoiding financial pitfalls. “Take It from Me” and “Keep in Mind” sidebars offer brief advice from peers and the authors, respectively. Ages 12-up.