Check you local battery trucks. They have batteries that they rotate out of consignment and need to sell them before they do not sell. In other words, if they have a battery rack at a local shop and that shop does not buy any of the batteries from that rack within the allowed time, they have to rotate them and put in new batteries after about 6-8 months. The ones he takes away are the ones he will sell cheap. Usually about 30-45 each. You can also get car batteries for about 20 bucks.