Investors can choose from literally thousands of exchange-traded funds (ETFs), which means picking the best ETFs can be daunting.

More than a dozen funds track well-known basic indexes such as the Standard & Poor's 500-stock index, Dow Jones Industrial Average and Russell 2000. Scores of other ETFs try to beat those benchmarks by carving out certain types of stocks or bonds, or by emphasizing things such as value or share-price momentum - anything to give them an edge.

We've picked The Kiplinger ETF 20 with an eye toward low fees, making this a list of the 20 best cheap ETFs to use to reach your investing goals. Our selections will give you anything from broad market exposure to narrow tactics meant to help you fill specific gaps in your portfolio. Read on to learn about these 20 ETF picks.

iShares Core S&P 500

Market value: $166.4 billion

Yield: 1.7%

Expense ratio: 0.04%, or $4 per $10,000 invested

Trades commission-free at: Fidelity, Firstrade, Vanguard

Standard & Poor's 500-stock index is synonymous with the U.S. market and is the benchmark against which most large-cap managers are judged. Stocks such as Exxon Mobil (XOM), Apple (AAPL) and Bank of America (BAC) dot its holdings.

All three S&P 500-tracking funds easily rank as cheap ETFs. But the iShares Core S&P 500 (, $294.47) has a key structural advantage. The classic S&P 500 index ETF - the SPDR S&P 500 ETF Trust () - is structured