I honestly have no idea. Ive never even seen a G1.
It could sort of work for local stuff. It might pull up a price for a Target or Best Buy or something but you would have to look up a local one and check stock / price yourself.
It think right now its best used as a indicator as to whether or not you're getting a good deal. If it finds 10 places online that are selling your item for 40% cheaper, maybe you should look somewhere else.