Howdy.
I am a beganner road biker my self. Propelled into it by my Spinning class instructor.
My advise is prob different from others here since I am not 100% sold on it as a great investment as a fun sport or exercise. I'm saying this because the benefits you achieve by training on a bike vs on s stationary bike is very similer. At the same token, a decent Road bike will be in the neighborood of $700-$800 for a starting bike.
So I would suggest taking a few spinning courses and meet some of your local road bikers and see if they have a spare you can use and ride with them on. This way you can findout if this sport is for you before you take such a investment in it.
I am borrowing my Ex's Trek 1100, good balanced bike, but so very un comrfortable to ride(I am told you get used to the postering)