You can invest in a commodity that has always served as money, with just a little cash and at a discount to the actual price of copper. Investing in durable commodities like gold, silver and copper protects your purchasing power in inflationary times. With the US printing new money by the trillions this is a very real concern.
Understand that US Pennies up to 1981 are 95% Copper/Cu and Canadian Pennies up to 1996 are 98% Copper/Cu. After these dates pennies have been made from copper coated zinc (US and Canada) and copper coated steel (Canada) in a process called debasing.
Find a good supplier set up to supply at the level you want to invest at. Some suppliers focus on 1 lb to 10 lb lots. Other suppliers focus on 68 lb flat rate USPS boxes. Some suppliers will sell you a ton (2000 lbs) or more at a time.
Go shopping for your copper pennies. Sources include: a) e-Bay.com - Copper Bullion category.b) Copper Cave www.coppercave.com for smaller lotsc) The Portland Mint www.portlandmint.com (larger lots)d) Realcent Forum http://realcent.forumco.com/ (various sellers and good place for education