Copper is traded on the Commodity Market, and therefore, the price changes daily.
The price of copper is predicted to fall during 2007 to something like US$7,700 per metric ton while its peak price in 2006 (May) was US$8,800 per ton.
This is due to output growth of copper-concentrate ore, the main raw material for producing electrolytic copper.
You may also have to consider the Futures Market, say 3 months out, which may well be lower than today's price.
If you need precise daily figures, you need to sign up to one of those commodity news services.