Suppose I'm convinced that silver will reach $100 before Dec 2015 (in 2 years).
From this site:
http://www.barchart.com/commodityfutures/Silver_Futures/options/SIZ15?mode=i&view=
it looks like I can buy a call option on a 5,000 troy ounce silver contract with strike $50 for only $1,345...