Personally if you want to learn how one is set up you can get a DJI F450 that's already built and ready to go.
http://www.ebay.com/itm/DJI-F450-Qua...item58b6e5612b
Since the frame is open you can fly it already and you will have a good idea how it's all put together for future builds. It's also made of high quality components.
http://www.ebay.com/itm/DJI-F450-Qua...item58b6e56112
Here are some that are actually cheaper, but the FC is the less capable KK board.
http://www.ebay.com/itm/F450-FlameWh...item2325658c72
Here's one you need to add radio gear to.
http://www.ebay.com/itm/DJI-F450-Qua...item2a45e96308