I just searched the completed listings of Ebay, the G7 has been selling for between $290 and $340. Ebay has some really good sellers too, if they say excellent+ or mint condition, rest assured it is... That is the way I would reccomend. You could also run all over town and see if any local retailers still have theirs in, which would likely be in the clearance section, but its doubtful...

*edit - strange that canon would mark the G7 $50 higher than its next model up... hmmm... Check out this listing that just finished -- link here