When you count your labor, I doubt you will make any money even if you get a better than average price. If you are doing it as a hobby project and realize it will cost you something as a net cost, it's up to you. I'd count your labor as twice minimum wage, which is the minimum it would cost you to pay someone else. I think you have to have a minimum number of posts etc. to sell on Forums, but not on ebay of course. I'd be hesitant to buy lots, since some pipes will likely go unused and unsold, hence raising the cost of the others. Some people do well with lots, if they have already allotted time to work on pipes and will do something with almost all of them, but they are a special breed of cat.
