Sarcasm.. you picked it up!!........LOL
Adding drop bars to your commuter will not be cost effective, as they are often the most expensive component in the gruppo...
So.. CL is your friend in this case... buy an older road bike... and go from there... keep an eye out for a strong and quality/sturdy wheelset, that can handle the rigours of daily commutes (like massive potholes that can't be avoided due to traffic)...upgrade tyres to commuter duty ones... add fenders... lights.. etc..
and post pics.. of your find and build...