This post comes from Jeanine Poggi at partner site The Street.

"Save money. Live better." Wal-Mart has based its business off this iconic motto since 2007. Prior to the catch phrase Wal-Mart operated by the slogan "Always low prices" for nearly 19 years. But starting in 2011, it appears the retail giant may have abandoned its business model of everyday low prices, further hampering its already pressured domestic sales.

In the first three months of the year, Wal-Mart's prices on food, health and beauty products and other general merchandise were nearly identical, if not a bit pricier, than archrival Target.

According to pricing studies conducted by Customer Growth Partners, a consumer research firm, January, February and March all revealed Target's prices were lower than Wal-Mart's. The monthly study, which is conducted in four states, compares products across segments, including 30 fresh, frozen and nonperishable groceries, eight household chemicals, paper and other consumables like detergent, seven health and beauty aids like shampoo and counter medicines, and 10 general merchandise items like apparel and toys.

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In CGP's analysis for the first three months of the year, Target held a 0.6% price differential over Wal-Mart. This was the first time since the firm began conducting these studies in 2006 that Target displayed lower prices. In the past, Wal-Mart has typically maintained a 2% to 4% advantage over Target, says CGP president Craig Johnson.

If you then factor in Target's new Redcard loyalty program, which offers users a 5% discount, that price difference widens. Of course, not all of Target's customers are Redcard holders. Johnson estimates that the loyalty program makes up about 13% to 16% of sales.

But the usage and penetration of the Redcard appears to be increasing, as it provides shoppers at least a 5% discount on new, higher cost, but generally undiscounted consumer electronics items like Apple's new iPad 2 andNintendo's3DS.

Wal-Mart does not offer a similar program, which could put the company at a further disadvantage moving forward.

In a separate study conducted in January by Kantar Retail of just one Wal-Mart and one Target store in Massachusetts, it found that Target's prices were about 2.8% lower than Wal-Mart's. But the research firm noted that Target's low prices are more dependent on temporary sales. This means shoppers need to be willing to change brands based upon the promotions being offered in order to really notice a few extra bucks in their wallets. Post continues after video.

Groceries cost less at Wal-Mart

Two categories, in particular, where Wal-Mart remains a price leader are groceries and nonperishable home goods like paper towels and light bulbs.

While Target has grown its P-Fresh assortment by leaps and bounds, Wal-Mart continues to dominate the sector. About half of all of Wal-Mart's merchandise falls under the groceries segment, while CGP estimates that 15% to 20% of Target's merchandise are groceries.

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According to the Kantar study, Wal-Mart was cheaper in edible grocery items by about 1% and has a 3.4% advantage over Target with non-grocery home goods.

Kantar purchased a basket of 13 edible items, finding price differentiations like a tub of Land 'O Lake butter for $3.48 at Wal-Mart and $4.39 at Target. It is also worth noting that five of the items Kantar studied in the category were on sale that week at Target, while just one item at Wal-Mart was a special. If these items were not on sale, Wal-Mart would have been cheaper by 6.2%.

Food inflation has put pressure on all grocers, but Wal-Mart has been less willing to accept increases in general merchandise from suppliers or pass along those higher costs to shoppers, allowing it to hold its title as the biggest seller of groceries in the U.S.

In non-groceries, a package of GE Soft White light bulbs, 60 watts, sells for $1.88 at Wal-Mart and $2.29 at Target, while a four-pack of Duracell pre-charged AA batteries are $12.19 at Target and $11.37 at Wal-Mart.

Health and beauty products lower at Target

Wal-Mart was easily beat in the health and beauty segments, with both CGP and Kantar saying Target has a clear edge on price.

In January, Target had a 7.3% advantage over Wal-Mart, according to Kantar. But the research firm noted that this was partially because nearly 30% of the items studied in the category were on sale at Target, while only one was on sale at Wal-Mart. Still, even without those sales, Target would have been 5.5% cheaper.

Wal-Mart has been struggling with its image among core shoppers since it removed thousands of items it deemed unprofitable from its shelves starting in 2009. While it is currently restocking some of that merchandise, the process is slow, and has left a sour taste among some customers.

But an even bigger concern has been the perception among shoppers that Wal-Mart does not offer the same savings it always had. "We believe that the price leadership perception, in fact, is a greater issue for Wal-Mart than destocking the fifth or sixth brands in a particular category," Johnson says.

As a result, Wal-Mart is poised to report yet another quarter of sagging sales in the U.S. when it releases its first-quarter results on Tuesday. This would mark its eight consecutive same-store sales decline domestically.

In comparison, while Target's sales haven't been anything to get overly excited about, their sales have trumped Wal-Mart's. While Target has typically been considered a high-end discounter, amid the recession the company introduced several new initiatives that have helped to erase this perception.

But it appears, at least, that Wal-Mart returned to its deep discount roots by the end of April. Wal-Mart's prices were 2.8% lower than Target's in April, according to CGP, but including the Redcard, Target had a 2.3% favorable edge.

Wal-Mart may be headed in the right direction, but based upon analysis for the first three months of the year, it looks like a sales turnaround is unlikely in the first quarter.

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