Application to check for lower prices

I need to find an application which tracks eBay and other websites to ensure you have the lowest priced item available for sale.

It should have options to browser a certain site as well.

Item listed on eBay is $9.95, you list for $9.94 and then if someone lists it for $7.95 you re-list at $7.94


seems like this one

Is there a more systematic approach? Price is not an issue and this is for a corporate client who uses Magento.