Power pack D is what you need for the motors.
or you can get this package
http://www.altitudehobbies.com/flit...k-for-flitetest-electrohub-quad-upgrade-setup
or this package
http://www.lazertoyz.com/FT-ElectroHub-Power-Pack_p_517.html
You can buy these elsewhere possibly for a bit less but Flite test and their affiliates sell a convenient package.
Then you will need a flight controller. Two popular ones are the
KK2 You can also get this from AltitudeHobbies
or the
Naze32 Acro It can be found elsewhere too.
The KK board is probably a bit better for beginners because you can program it on the board. The Naze32 has to be programmed via a computer but it is more powerful. You can find flite test videos for the KK board I think. The RCModelReviews build covers the Naze32. There's lots of YouTube.
There are some different packaging choices; the mini KK is the same but smaller. The Naze32 is available with no pins installed vertical pins or horizontal pins.
There are other options for flight controllers but keeping it simple...
You will need a radio system. A good inexpensive one is the
FlySky i6 with the iA6B receiver You can also get it from hobby king as the
Turnigy i6 but it comes with the less preferred receiver. There are lots of other choices but the
i6 is a good value and quite inexpensive. You should research this a bit before buying since you may decide to get something more capable/expensive
You will need batteries and a charger. Something like this
2200mAh 3S 35C is probably good to start but I'd need to look some more.
For a charger you can get by with something like this
B3 but if you are serious you will want a
4 button computer charger. Note that this ones needs an
external power supply. They take some study to use safely so the B3 is a good place to start if you not comfortable with that yet. Most lipo fires happen due to charging mistakes. Always uses a lipo charging sack or better, always balance charge and never leave unattended.
You will also need various tools and miscellaneous bits to build the thing...