By Joel Larsgaard, dealnews contributor While the realm of grocery shopping has always been ripe for money saving tactics like extreme couponing, it has largely been exempt from the trend towards price comparison; up until recently, if you wanted to know who had the best price on a particular item, you had to drive from store to store to find out, or at best manually check several sites online. Enter mySupermarket.com, a new site that compares the prices of online groceries (both foodstuffs and otherwise) across a variety of stores. Having been successfully operating overseas since 2006, mySupermarket claims to save shoppers an average of 17% over the use of any other single retailer. But can this online grocery shopping comparison site save U.S. consumers both time and money? Minimize Grocery Costs with Price Per Unit Analysis and Free Shipping mySupermarket searches for the lowest-priced groceries across some of the most prominent retailers on the web, including Costco, Walmart, Amazon, Soap.com, Diapers.com, and Target. As such, mySupermarket's aggregation technology is similar to that of Google's Shopping search, but instead specifically hones in on the savings to be had on household grocery items. As shoppers add items to their basket, mySupermarket keeps a tally of savings in the bottom right hand corner of the checkout cart. There's even a "Savings Zone" with recommendations on how customers can save more. For instance, mySupermarket will recognize that a single bar of Dove has a higher per-unit price than that for a 6-pack; while the total cost of the larger quantity is more expensive, the cost per bar is less. By nature of the tool, your cart will likely contain items from several different vendors. However, shoppers only place a single order with mySupermarket, which then sends each order to the respective retailers for filling. That means customers can expect to receive their items in several shipments. But mySupermarket's shipping optimizer ensures that before checkout, shipping costs are calculated and even lessened by way of combining store shipments; as a result, however, you may end up paying a higher base price for an item in order to get that reduced delivery. mySupermarket also offers free shipping with a minimum purchase of $75, though it's a bit tricky to grasp at first. The $75 minimum is typically met when mySupermarket either rearranges purchases to decrease their total shipping costs (and therefore increases the purchase total) or by charging the total shipping costs up front and then refunding the total via a PayPal account within seven days. To put the mySupermarket free shipping to the test, we placed about $75 worth of groceries into our cart. In order to reach the minimum for free shipping, though, the mySupermarket automagically raised our grocery prices almost $7 to meet their shipping minimum. So technically we received "free shipping" but were no longer getting the lowest price for all our items. mySupermarket Lets You Skip the Saturday Errands The major benefits to mySupermarket are that it's easy to use and navigate. Shopping online for non-perishable essentials in 15 minutes — and knowing that mySupermarket has presented the cheapest options — has some obvious perks. Additionally, mySupermarket not only compares the total price of items but also includes the price per ounce or unit. This figure can help consumers make an informed purchase and discern the best value for their needs with just a glance. With 544 diaper choices, 123 toilet paper options, and 355 different varieties of ground coffee, stress over what product and in what quantity can easily set in, but being able to sort by price per unit or overall price really adds some peace of mind to the process. But Selection Isn't Good Enough to Completely Replace a Trip to the Store Despite its ease of use, mySupermarket can't replace a trip to the grocery store entirely, as perishables like milk, fruits, and vegetables aren't available. Moreover, generic brand items are nearly impossible to find. While shoppers might score the lowest online price on Tide or Cheerios, there aren't many store-brand items available, so fans of Kirkland, Great Value, and Up & Up will have to visit brick-and-mortar locations to find those lines. And unfortunately this one factor really hurts the usefulness of mySupermarket as buying private label products can slash 25% off your grocery bill. Specialty items also don't make the cut, either. Take dog food for instance: mySupermarket aggregates the best prices on just a few brands. And although there are a ton of different varieties for each brand, there are still some gaps in inventory that'll require a trip to the local pet store. Inventory aside, the addition of user reviews to products would be really helpful as well. Being able to read about what fellow consumers like and dislike could make the site more appealing and could offer another great sorting option. Alternative Online Grocery Options As Amazon expands its own online grocery service, AmazonFresh, we wonder how long the megaretailer will participate in the mySupermarket experiment. With lower thresholds for free shipping, the ability to ship fresh produce and meats, and an already enormous customer base, AmazonFresh will likely make more sense for most consumers as it begins to roll out across the country. Other consumers may find Mygrocerydeals.com helpful as a pre-shopping planning tool. Simply input a grocery list and the site will seek out the best deals available in a specific area. While in-store shopping is still required, Mygrocerydeals does incorporate current sales promotions and flyers into consideration and includes off-brand products in its results. The Bottom Line The UK version of mySupermarket sells meat, dairy, produce, frozen foods, and even TV dinners. If the U.S. version develops in line and thereby can eliminate the need to make a trip to the store altogether, the site could make some big waves in the grocery industry. In the meantime, you can at least score cheap laundry detergent as new users save $20 off their first purchase of $75 or more. Related dealnews Features: Private Label Products Will Slash 25% Off Your Grocery Bill Meat Matters: The Ins and Outs of Ordering Beef Online Does Grocery Shopping Online Make Sense for Your Lifestyle? Follow @dealnews on Twitter for the latest roundups, price trend info, and stories. 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