A little bit of everything. For many investors, checking the price of any single commodity on a consistent basis may be too complicated. ETFs have made investing in a single commodity easy, but they also offer investors the option to invest in a number of commodities within a single fund. Some advisers suggest a more diversified approach. "Our preference is to do it through a broad-based basket of commodities—not to try to pick and choose commodities," Miccolis says. Experts say this strategy can be a useful for investors who are wading into the sector for the first time. Miccolis says he has used a combination of mutual funds and ETFs in the past for his clients including Oppenheimer Commodity Strategy Total Return (QRAAX) and PIMCO Commodity Real Return Strategy. Lydon recommends iShares S&P GSCI Commodity-Indexed Trust ETF (GSG) or PowerShares DB Commodity Index Tracking ETF (DBC).