Also, how simple do you want it to be? I mean, I know of some kits that equate to "unbox, turn 4 screws, and plug in some wires" type of kits, and there are others that would require some soldering, programming, more programming, learning curve, crashing, reprogramming, flying for 10 seconds, crashing, etc.
As cranialrectosis stated, there's a lot to ask on this one. If you can give us a little more background on what you expect, what equipment you already have (or don't have - that's ok too), we can get you pointed in the right direction.
Oh, and expect several directions, and people saying one avenue is better than another because of personal preference. A lot of this hobby is like any other - you have the "Ford vs. Chevy, Apple vs. Android" type of mentality, but understand that some suggestions may be "better" overall, but may not be better for what you really want to accomplish.
Also, you can get some pretty cheap toy grade quads from China that are nearly indestructible. The JJRC H31 is waterproof and around thirty bucks from an American warehouse, ready to fly. Batteries, controller. Ready to fly. The Furibee F36 is a great little indoor quad, same deal ready to fly and around ten bucks. I mention these, because they're really inexpensive and a whole lot of fun.