There are quite a few shopping comparison apps for the iPhone (Amazon’s is excellent) — the idea being that if you’re shopping on the high street and see something you want to buy, you can quickly look it up online and see if it’s cheaper anywhere else. Now Google is getting in on the action.

Google Shopper for iPhone is a free app that can identify a books, CDs, DVDs and video games both by their cover and their barcode — just launch the app, point the iPhone camera at the item you want to identify and as long as there’s an internet connection, the best online price should be quickly returned.

You can also search for items by speaking or typing its name, but unlike Amazon’s equivalent app, Google Shopper won’t yet recognise an item based on a photograph that doesn’t at least contain some text.

Once a product has been found, Google Shopper will return a list of results that includes both online stockists and bricks-and-mortar stores near to your current location — useful if you’re in a fix and don’t know the local area. You can also mark results for later reference and share them with friends over social networking services, but the app only works in the UK and USA, so it’s no use for European travellers.

[Google Shopper on iTunes]