I wouldn't go as far as crowdsourcing quite yet, but yes, all in disguise. So from the users point, they hardly have any work to do when it comes to the searching. And we'll let them know how the search goes from our end :)
If a user asks enters a product that is already in the database and you already have a better price, notify him in a mail a few minutes later that you have a better price and he will be impressed.
If a user enters a product that is already in the database and he has a better price, -send the first user a notification.
Additionally you will habe a growing number of sources for anything tjat you can poll and mine.