Wal-Mart (NYSE: WMT) could play a big role in helping Earth-friendly start-ups survive. The Wall Street Journal reported that Terracycle, a small, private company that fashions products out of difficult-to-recycle packaging, is hoping that large retailers like Wal-Mart will take up its cause more consistently -- and help the tiny company finally turn a profit. Wal-Mart carried Terracycle's wares during a promotion for last month's Earth Day. In one clever touch, the retailer stocked Terracycle's backpacks, crafted from Kraft's Capri-Sun packages, next to the actual Capri-Sun beverages