Could somebody please offer a better explaination of the economics of using a Bitcoin to purchase physical goods? Or how something generated for free can acquire value and be traded to real money.

All the online videos and text (I have found) explaining Bitcoins offer nothing to the economics of it.

We all know you can't print your own paper money, so why should Bitcoin work when you are doing the electronic equivalent??

In a bartering system, it's still work for work. I can't see how mining benefits anybody other than the GPU manufacturers and power companies.