I found this in an article entitled "Mr. President, why not buy out Afghanistan instead of invading?" that is published over on OpEdNews. You might like to click through and read the whole thing. It's interesting.
If you want to choke off the terrorist elements operating in Afghanistan and Pakistan, you have to treat them like any piratical scourge. You have to disrupt their operations, deny them safe haven, and destroy their supply lines. We know where the money is coming from. It comes from the opium trade. That supports the corrupt government that provides safe haven. It is also a major source of revenue for supplies.
For about $6 billion USD we could buy the entire wholesale value of the opium crop for the next 10 years. That is about what we'll spend in 2 months covering the cost of deploying 30,000 combat troops.