A good rule of thumb when doing any bulk shopping for food is to avoid buying anything that will expire or spoil before you have a chance to use it. The best bulk purchases for the kitchen are items that have long shelf lives. That way, you can spread out the consumption and not get tired of the pallet of food you've just bought. Good examples include canned goods or boxed goods with distant expiration dates. Products like canned tuna or soup can be great values; both are around 30 percent cheaper in bulk at the warehouse clubs than at standard grocery stores [source: Wallet Pop]. A staple like rice also makes a good choice. Rice is very inexpensive in large quantities, and white rice can last up to a year. But be careful. Brown rice has a shorter shelf life of only about six months [source: Shelf Life Advice]. Another surprisingly good investment is pepper, which can last one to three years if you buy whole peppercorns. But ground pepper lasts only six months to a year [source: Shelf Life Advice].