Statista is the largest and most extensive statistics platform of its kind in the world. With a team of over 120 statisticians, database experts, analysts and editors, Statista provides students, faculty and researchers with an innovative and intuitive tool for researching quantitative data and statistics from 18,000 sources and on 60,000 different topics. With many thousands of downloadable reports, studies and dossiers, Statista provides huge coverage of data relating to economics, society, politics and environment.
Capital IQ provides a variety of Commodities - precious metals (including gold spot prices), oil & gas etc. and Macroeconomics including GDP, population, currency etc. It can be searched in a variety of ways e.g. Markets > Macroeconomics and then search for a country.
You can then click on the commodity or economic indicator you want to pull up the data and get options to change the time series, export to Excel etc.
Capital IQ is a key resource for prices and raw data on commodities e.g. gold prices.
IbisWorld and Statista provide various reports, trends and data on many commodities e.g. search for 'gold' in Statista.
Other sources of free information include: