Using the above example, you could have 30 stocks (assuming none are funds, which would carry a management fee), and with each one costing $1 per month to invest in, your still looking at $360 per year in commissions. However, not only would you have to actually chose 30 securities to begin with, but it leaves you exposed to very high risk, even if you diversify by country, sector and market cap. This creates an unrealistic situation. While this is an incredibly cheap form of investing, it would take a lot of time for a typical investor to narrow down an effective, diversified 30 securities in which to be invested. This is why paying a simple management fee makes sense. While these fees can get extremely expensive, they can also be dirt cheap. Take, for example, this list of the 100 cheapest ETFs. The cheapest ETFs on the list are the U.S. Broad Market ETF ( SCHB) and the U.S. Large Cap ETF ( SCHX) from Charles Schwab. With an expense ratio of just 0.04%, investors only pay $4 per $10,000 invested. That's incredibly cheap. Overall, the list contains 37 ETFs with an expense ratio of 0.10% or less. And the list doesn't just include broad baskets of domestic stocks, either. It includes bond funds and international exposure as well, helping with the task of proper diversification. From our example in my first article, our diligent saver entered retirement with about $600,000 in his or her Roth IRA, and another $60,000 or so in his or her taxable brokerage account. The same principles/ideas that I'm applying to the Roth IRA can also be applied to the separate, taxable brokerage account, but let's look at just the retirement account. The commission-free ETFs and mutual funds are not set in stone. They differ, accordign to the broker you use. So perhaps,E-Trade Financial offers some that you would prefer, or maybe TD Ameritrade has the ones that you like more. It only takes a little exploring on each broker's Web site to find what fits you best. In fact, both Schwab and TD Ameritrade offer more than 100 commission-free ETFs, some starting as low as the 0.04% expense ratio that we talked about. Going a bit above the 0.04% to 0.10% range that we discussed earlier, let's assume all of the funds we invest in come out to an average expense ratio of 0.15%.