At your price range, I'd go for a used bike off craigslist and brush up on some mechanical tinkering from videos on parktool.com and youtube. As you've heard, the bad news is you're not going to get anything decent in this price range.

If you have to start on a cheap bike do yourself a favor and don't judge road cycling until you've ridden something good. On a decent bike, road cycling is addictive.