across the wire

I have been bitten by the eBay bug. I recently purchased an Ani Difranco CD "UP UP UP UP UP UP" (1999) for under $6. That includes S&H! Now I am searching for all kinds of stuff. It can be an illusion to how much money you might save as I have found that shipping and handling costs are often times crazy ridiculous (one CD from one dealer costs 7.95 USD). I just put a bid (of 0.01 on another CD). I think I need help...

Some people make a business of this. What is the secret? Do they buy online then sell again? Do they buy from yard sales and then sell online? How do people actually make money at this?

For my next big search - kitchen utensils and cookbooks. This one in particular.