You're in luck! You can get cameras nowadays for even less than $100 that are better than the iPad 3's camera. Any Canon point & shoot over 5 megapixels will fit the bill (I saw one at RadioShack on sale for $59). Best Buy has a ton of cameras that have more than twice the resolution and are well within the price range you're looking for. Look at Canon, Nikon, and Panasonic Lumix brands.
I can personally vouch for the Canon Powershot Elph 110 HS, 16.1 MP (reg price $299, on sale for $199 at BB) and my personal favorite, Nikon Coolpix S8200 16.1 MP (reg $329, on sale for $229 at BB). Both cameras have excellent sensors, white balance, image stabilization and a ton of features, and have produced pics that look absolutely stunning on the iPad 3 which make the iPad's camera pale in comparison.