[Simplistic]

if you had 100k USD when you're in your early 20s and threw it in an indexed mutual fund for 40 years with an average return of 11.83% you'd have 8.7 million dollars. this is without adding anything to it. (11.83% is based on the past 30 year return of the DJIA)

so for people who think that you need money to invest you're wrong. people NEED to start young and have something to fall back on.