Open an IRA, or direct the amount of your refund toward your contribution. Today's your lucky day. Whether you go biotech or blue chip, choose something they use or identify with. And it also encourages them to be aware of the stock market and gives them an incentive to follow it. Or maybe you want to buy into a stock fund for yourself.
Rich people start off as poor people.
Set up a rainy day fund. I like for them to set up a separate mutual fund account. The money is there in an emergency, but since you can't just empty it out by writing a series of little checks you're less likely to touch it. The standard rule of thumb is to sock away three to six months of living expenses. Smart buys 5.