If you want a lame excuse for not investing for your future, you've come to the right place. Take your pick of the ones I most frequently hear:

  • "I don't have any extra money to invest."
  • "I've got decades until retirement."
  • "Stop harassing me, Dayana, or I'm telling on you to Mom and Dad."

Save your breath: I've heard them all. If you don't yet have a discount broker, get one already. (All your questions about the technicals are answered here.) If you're strapped for investing ideas, just start with an index mutual fund. Short on cash? Read on.

What I tell those who will listen (and my brother) is that the key ingredients to market-beating returns -- no matter how much money you have -- are time, amount invested, and rate of return. But when investing smaller amounts of money, there's an additional consideration to ponder: cost.

The "costs" of investing in most cases come down to one line item on your money-management budget: your broker. So to make whatever pittance you have to invest go as far as it can, cut out the middleman.

One of the easiest ways to trim fees is by buying stock directly from a company, bypassing all brokerage charges. You can do so via investment programs called DRIPs (dividend-reinvestment plans). (My colleague Mathew Emmert calls DRIPs "the closest thing to getting your shares straight from the tap." He's a clever boy.) DRIPs allow investors to add as little as 10 bucks a pop to buy more company stock. Surely you can free up 10 smackaroos from your budget every week. I bet after reading the next paragraph you'll be able to.

Let's say your DRIP company grows at a rate of 13% per year over the next 60 years. Further, assume that you add $10 every week to that investment for the next 60 years -- just $520 a year. How much pre-tax money will you have in 60 years?

$5,600,000.

Whoa there, cowboy... put your wallet back into your pocket. Before you get distracted by all those zeroes, read the scenario once again and note one key piece of information: "... over the next 60 years."

I don't know about you, but I need to start sipping my savings in less than 60 years. So what happens when we tweak the scenario to reflect a $40 weekly investment -- a little more than $2,000 a year -- into the same company for 30, not 60 years? How much pre-tax dough are we talking about?

Six hundred and ten thousand, three hundred and twenty-two dollars. (I spelled it out because $610,322 didn't look so impressive compared to that "$5,600,000" hanging out a few paragraphs up.)

My point? What matters the most is how much time you have to invest, not how much money you have. While both are important, the difference between the investor saving $2,000 per year for three decades and the one saving $520 a year over 60 years is profound.

So the next time I ask you why you're not investing anything -- dear brother -- I don't want to hear any excuses.