Charles Schwab and the Vanguard Group offer some of the cheapest ETFs on the market. For instance, the Schwab U.S. Large-Cap ETF (NYSEArca: SCHX) and Schwab U.S. Broad Market ETF (NYSEArca: SCHB) are the two cheapest ETFs on the market with a 0.04% expense ratio. The two equity ETFs are good options to build out a core component of any diversified investment stock portfolio. [Build a Dirt-Cheap Portfolio With These ETFs]

Additionally, the Vanguard Total Stock Market ETF (NYSEArca: VTI) and Vanguard 500 Index (NYSEArca: VOO), which both come with a 0.05% expense ratio, are another two options that investors may consider.

Investors can also access diversified international markets with the Schwab International Equity ETF (NYSEArca: SCHF), which has a 0.08% expense ratio, and Vanguard FTSE Developed Markets ETF (NYSEArca: VEA), which has a 0.09% expense ratio.

The close attention to fees has helped wealthier investors save on costs in investing over the long-term. Through cheap index-based ETF options, any long-term investor can also save on fees, paying expense ratios that are comparable to institutional fund share classes.

For more information on ETFs, visit our ETF 101 category.

Max Chen contributed to this article.