I was reading the new article on the New York Times related to using your mobile phone for shopping comparison functions that may save you money and in the end even help offset the cost of your new smartphone. In particular, the T-Mobile G1 has a couple of bar code scanning/shopping comparison applications available to help you get the best price. While the G1 is getting all of the attention for this capability, there are also other shopping applications that may be quite helpful that require you to enter search terms using your phone's QWERTY keyboard or keypad.
I used the S60 application, Slifter a couple of years ago on my N95 and it works pretty well. I am sure there was a barcode scanning shopping application too, but I haven't been able to find it again online. Slifter is also available for BlackBerry devices. There seem to be a few good shopping comparison apps for the iPhone, including Save Benjis, Slifter (multi-platform), and Checkout SmartShop. With many of these devices having QWERTY keyboards, shopping can be just as fast as scanning a barcode on a product too.
After some fairly extensive searching though, I am surprised there haven't been more mobile shopping comparison applications since it seems to make perfect sense. I often even just use the Google Products search for price comparisons and also to find reviews on product before I buy them in the store. Then again, from time to time I do lose my signal in the middle of the mall so a shopping application on my phone may not help that much.
Do you have a recommended mobile phone shopping comparison application?