Akihabara can also be a tourist trap. Although a must see, it is not always going to be the cheapest place to buy electronics, especially cameras. Check out Yodobashi Camera at Shinjuku station. You should also price the item in your home country before going to Japan. This way you'll have a reference price before you start shopping. Double check that it's the same item too. Japan has some electronics that are far better than the items you can get in your home country!
Be forewarned that before you buy any electronic items like phones and music gadgets, be sure to check with the store if they will work in your home country since a lot of items appear to be cheaper compared to prices at home