I take my pocket change at the end of the day and drop it in a jar. I put away about $1 a day, that's just $7 a week. At the end of the month, I'll have about $30.
Since this is money in my pocket, I've already paid taxes on it in the form of withholding from a paycheck. (If you're self-employed, that's not true, but we'll ignore that to keep things simple.) Every month, I deposit my savings in a Roth IRA account, where it can grow tax-free and - more importantly- it can be withdrawn tax-free in the future.
Growing tax-free for 30 years, with a 10% annual return, my investment account will be worth $67,815. (Stocks overall have returned an average of more than 10% a year since 1926, so buying a broad-based stock index fund the Vanguard Total Market Index Fund (VTSMX) is the easiest way to capture that kind of growth.)
http://www.forbes.com/funds/Tearsheet.jhtml?tkr=VTSMX
