Wal-Mart Stores is bringing its economies of scale to organic groceries. The retail giant said this morning that it is teaming up with Wild Oats to offer a wide range of organic fare at nonorganic prices. Wal-Mart said the groceries will cost about one quarter less than similar organic offerings. At first, the initiative will comprise about 100 different kinds of Wild Oats food -- including canned vegetables, spices, and salsa -- in about half of Walmart's 4,000 stores. The announcement comes two days after Target said it is expanding its lineup of organic and all-natural products.