Taking a pup to an obedience class may be high quality and simple, but it ain't cheap.
Doing it yourself (DIY) without expert guidance may be simple and cheap but not very effective.
The solutions -
DIY with Expert Guidance
DIY with Expert Guidance
Also see Stop Puppy Biting
So what's your choice? You need all three types of training. Train easy or train hard - it's up to you - the dog trainer!