NOTE: If you are unable to purchase the Vanguard Federal Money Market Fund at your brokerage, you may substitute a similar money market fund in its place. At Fidelity, you can use the Fidelity Money Market Fund (SPRXX). At Schwab, you can use the Schwab Prime Advantage Money Fund (SWVXX). If no suitable money market fund is available at your brokerage, you can use the iShares 0-3 Month Treasury Bond ETF (SGOV).