I guess I had the wrong idea of what "flipping" was. I always assumed it meant finding an under valued treasure (garage sale, gift from friend, dumpster, etc.) and then selling it for a profit on ebay, with minimum work/expense put into it. If you are adding value by cleaning, lubing, replacing parts before selling, then you may never recover all that you put into it, but at least you have a relaxing hobby that kept a bike out of a landfill.