Bigger packages don't always offer better values. By David Muhlbaum, Senior Online Editor April 29, 2015 Plenty of us love to shop at big-box stores like Costco and Sam's Club. But not everything there is a deal. You need to remember that bigger isn't always better. In fact, when you start really comparing prices, you’ll find that sometimes, smaller packages at the grocery store often cost less per unit supersize containers. And of course, there's time to consider: Will that giant container of tomatoes, face cream or olive oil expire, spoil or simply lose its appeal before you've used it up?See Also: SLIDE SHOW: 14 Things Not to Buy at Warehouse Clubs Here are some everyday items you should avoid buying in bulk. Produce is an obvious one; it goes bad quickly. If you don't plan on serving roasted red peppers to 12, that big bag is going to be hard to get through. Plus, prices on produce tend to be static at warehouse clubs, while at the supermarket fruits and vegetables that are in season are often cheaper. Soda has a much longer shelf life, of course, but the better deal on this product is often found in the grocery store. Why? Shopping experts tell us that supermarkets often slash prices on soda to serve as a "loss leader" to get you into the store to buy other things. Keep your eye out for these frequent sales and you'll beat the warehouse club. Advertisement And here's one you might not have thought of: bleach. This household chemical starts breaking down from the moment it's made -- faster at higher temperatures. The effective shelf life is between six months and a year. So besides being unwieldy, a humongous bottle of bleach may lose its power to sterilize and whiten before you're done with it. If you don’t use a lot of bleach, opt for smaller bottles of low-cost generic brands or store brands from the supermarket over bulk-size name-brand bleach. We have guidance on many more products that are best bought in smaller quantities. Check out 9 other things you should never buy in bulk.