Latest News

"I spend my day chasing my daughter around, so I don't have the luxury of sitting at my computer," said Ms. Hughes, 29, of Reading, Mass. Many sites "have sales every other day, but I don't have time to go on and see if the things I actually want have made it onto the sale yet."

Now she doesn't have to.

With retailers' Internet prices now changing more often — sometimes several times within the space of a day — a new group of tools is helping shoppers outwit the stores. Rather than requiring shoppers to do the work by entering an item into price-comparison engines throughout the day, the tools automatically scan for price changes and alert customers when the price drops.

Some tools, including one from Citibank's Citi Card, even scour sites for lower prices after a purchase and help customers get a refund for any price difference.

Web sites that help shoppers compare prices and track online deals have existed as long as e-commerce itself. But rapid changes in pricing at many major retailers have made it more difficult for shoppers to keep on top of it all.

The research company Dynamite Data, which follows prices on behalf of retailers and brands, tracked hundreds of holiday products at major retailers in 2011 and 2012. During a two-week period around Thanksgiving, Amazon and Sears were changing prices on about a quarter of those products daily, a significant increase from the previous year. Walmart, Toys "R" Us, Kmart and Best Buy also changed prices more frequently in 2012.

Even the Web browser a customer uses can make a difference. The Web site Digital Folio, which shows consumers price changes, did side-by-side comparisons of televisions. On Newegg using the Chrome browser, the firm was offered a $997 price on a Samsung television. Using Firefox and Internet Explorer, the price was $1,399.

The firm found a difference on another Samsung television model at Walmart.com, where using Firefox yielded a $199 price and Chrome and Internet Explorer $168.

"A lot of times the price will have a big difference on consumer behavior," said Larry S. Freed, chief executive of ForeSee, which analyzes customer experiences.

One of the new price-tracking tools is Hukkster, introduced last year by two former J. Crew merchants. It asks shoppers to install a "hukk it" button on their browsers. Then, when a shopper sees an item she likes, she clicks the button, chooses the color, size and discount she is interested in, tells Hukkster to alert her when the price drops, and waits for an e-mail to that effect.

"We wanted a way to know, on a specific style we want, when it goes on sale," said a co-founder, Erica Bell. Hukkster also looks for coupon codes that apply to specific items, so a J. Crew nightshirt that was originally $128 came out to $62.99 after a site markdown combined with a 30 percent discount code that Hukkster found.

Currently, Hukkster makes money from referral traffic — it is paid a fee when shoppers buy something via a link from its e-mails. The founders say they are approaching retailers about ways of working with them by, for instance, offering personalized discounts based on shoppers' "hukks."

"Retailers are forced to do, say, 30 percent off all sweaters when what they're really trying to move is the green merino sweater. This provides them the option to do that on a one-to-one basis," a co-founder, Katie Finnegan, said.

Ms. Hughes, the Massachusetts mother, "hukks" items in specific sizes and colors, and then waits for the notification, like one on a Boden sweater she recently bought for her daughter.

"Now, of course, I'm hukking everything under the sun, including diapers, which I don't think is their target audience," she said.

Digital Folio charts the 30-day price history on electronics items at a number of retailers so shoppers can see not only where the lowest price is, but also whether that price might go lower still.