I started by buying batteries. When I'd have a couple hundred, Exide would send a truck to pick them up - I'd have a shipment twice a year. Gamedayron is right - buy by so much a battery. Have prices for L&G (lawn & garden), motorcycle, car/Lt Trk and heavy equipment. Learn the different classes of batteries. I spent a lot of time and miles scouring the countryside but it paid off big. There are hints of likely places. I'd usually get 20-30 from places with equipment in the yard - like logging skidders, truck repair shops and auto junk yards. The ones that came to me were usually those with just two or three batteries. I only had a couple days that I went out but didn't get enough to be worth it. Another tip - don't be shy and show them you know what you're doing.