Price wise, a true, drop-bar road bike is going to run you in the neighborhood of $1000 for an entry model. Like this:
http://www.giant-bicycles.com/en-US/...te/3881/36266/

A flat bar road bike can be had for closer to the $5-700 range. Something like this: http://www.giant-bicycles.com/en-US/....3/3876/36254/

(I'm just using Giant as an example; plenty of other brands out there). Used may be a good option, especially if you have someone knowledgeable that can help you with fit. Relatively new, used roadbikes tend to start in the $500, whereas more vintage ones can be had for $100-200 but may need a lot of work.