from ap: PORTLAND, Ore. -- Grocery shoppers will tell you that their bills are getting bigger from week to week. Many are already bargain hunting, buying store brands and using coupons for the best deals. But food prices are expected to rise further -- the USDA estimates that grocery prices will rise 3.5 percent to 4 percent this year and 3 percent to 4 percent in 2012. So what about exploring the option of buying in bulk? It may seem counterintuitive to buy more to save more, but with the right approach you can pocket significant savings.