Most climbing and bouldering gyms have a training area where you'll find a hangboard or two. These hangboards are more than sufficient to start hangboarding on as a beginner. Sure, you could go out and purchase one of your own. But out of personal experience that might make you more likely to overuse the hangboard and potentially injure yourself.
So I would steer clear of purchasing a hangboard when you are just starting out. If you are an eager beaver like myself, It's probably best to stick to gym hangboarding.