RE: j3 piper cub
The Cub is a terrific plane, but is definitely not for beginners! The manufacturer lists it as an intermediate plane, and they have good reason to do so. If you have never flown before, or if you have some limited experience, you willl spend more time, and a lot more money, repairing the plane than flying it. Check out the various threads regarding the Cub, particularly the one in the Parkflyers section.
Start with a good beginner's plane like the Firebird Commander or Slow-V. Once you have mastered this plane, move on to a more challenging beginner/intermediate plane like the Aerobird or the T-hawk. Once you have gotten good at flying this second plane, you will be ready to fly, and enjoy, the Cub. In the long run it will cost you less money and you will get a lot more enjoyment out of flying