Even some of the best grocers run with paper-thin margins of just a couple percent. So key players such as SUPERVALU (NYSE: SVU), Kroger (NYSE: KR), and Safeway (NYSE: SWY) have every interest in keeping every cost as low as possible. Commodities prices for food staples have already hit them, and now price increases from consumer goods companies Procter & Gamble (NYSE: PG) and Kimberly-Clark (NYSE: KMB) are in play, too.

P&G announced on Monday that it had raised prices on its Pampers diapers brand by 7%, while its Pampers wipes climbed 3%. Prices of its Charmin and Bounty paper products ticked 5% higher. Rival Kimberly-Clark also announced its own price increases of 3% to 7% on its Huggies diapers and wipes, following the company's recent 9% dip in quarterly earnings. Clorox (NYSE: CLX) is joining the bandwagon, plumping prices nearly 10% on its Glad bags, among other products.

These price increases are tentative steps for companies offering branded consumer goods, which have suffered from consumers' willingness to trade down to cheaper private-label products during financial hardship. With consumers already beleaguered by increasing gas and food prices, such companies have to tread carefully. In tougher times they fought to maintain market share with strategies like smaller packaging sizes while maintaining the same prices.

Still, as fellow Fool Rich Smith points out, parents often refuse to trade down on products for their babies. Diapers have pricing power. But P&G is leaving the price of its lower-priced Luvs brand unchanged, presumably to capture some of those willing to trade down, not to a private label, but to another branded category.

In a still more tenuous position are the grocery retailers themselves, who compete largely on price and not differentiation. How much of these price increases they have to eat themselves remains to be seen, but they're clearly in a weaker strategic position than the consumer goods companies or retail behemoths such as Wal-Mart (NYSE: WMT), which has greater bargaining power because of its size. With Wal-Mart knee-deep in the grocery business and e-commerce giants in the mix, traditional supermarkets are in a tough spot.

Of course, that doesn't mean there aren't bargains in the grocery aisle. I'm partial myself to SUPERVALU, which is deleveraging itself with its substantial cash flows. Trading at just nine times this year's earnings and with a clear value driver in the deleveraging, shares of SUPERVALU are in real bargain territory. So who do you think wins from price increases and who loses? Let me know in the comments below.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.