If this has already been posted, I apologize - but I thought it was a very cool idea. There is now an App that will tell you exactly who sells the product you are buying - and also the parent company! It is called Buycott!
From the Forbes Article about Buycott:
Once you’ve scanned an item, Buycott will show you its corporate family tree on your phone screen. Scan a box of Splenda sweetener, for instance, and you’ll see its parent, McNeil Nutritionals, is a subsidiary of Johnson & Johnson JNJ +1.3%.I bet there are plenty of companies that are having emergency meetings about this as we speak. Immediate information for consumers that helps them make decision on what to buy and more importantly - what NOT to buy. Makes me giddy just thinking about it. :)
Even more impressively, you can join user-created campaigns to boycott business practices that violate your principles rather than single companies. One of these campaigns, Demand GMO Labeling, will scan your box of cereal and tell you if it was made by one of the 36 corporations that donated more than $150,000 to oppose the mandatory labeling of genetically modified food.
I do want to mention that ever since the app was available Buycott is having problems handling all the traffic. According to an update to the Forbes article the development team is working to fix the problems and hopefully the bugs will be smoothed out shortly.