I'm always on the lookout for free apps from the App Store, and I've found an interesting shopping app that's worth a look. The app is called ShopAdvisor (iPad edition) and it's the kind of app that would get a lot of use in this household.
Think of a product you're considering purchasing. Enter it into ShopAdvisor and it finds the lowest price, both online and in local retail stores. You can opt to receive an alert if the price drops. It can also provide pros and cons of a pending purchase.
ShopAdvisor displays the most popular item in several categories. In electronics, by the way, the iPad is running away with the top votes.
I tried the app on common items and more esoteric purchases. Often local prices didn't show up, which wasn't a big surprise. There is also a price history graph which gives you the ability to make a more informed decision. Sometimes the info is a little strange. I looked at a Fuji 3D camera and it told me the low price was US$499, but the graph showed it selling for under $400. In fact, a Google search found it selling online for $299.00. That's a bit perplexing.
In general, the app worked as expected and was quite speedy. You can add items you are following to the home page, which is convenient. Much of the information it uses is sourced from ProductWiki. I didn't detect any biases in the pricing information. Amazon prices were well represented, and they are often among the lowest.
If you're a regular shopper, and most of us are, this app could save you some money, but my tests show it should not be your sole source of pricing information. The app is a 3.7 MB download and requires iOS 4.3 or greater. The developer also offers an iPhone version of the app, but I like the increased real estate on the iPad screen.