This thread is missing the obligatory GMC Denali pitch so here it is. I purchased the older version from Amazon (reportedly available from walmart as well) as my first road bike for $159. The current Denali on Amazon is the Denali Pro, a more traditional road bike version going for $325 but I can't speak to that one.

The Denali is a kind of hybrid on a road frame, mountain bike drive train, 700x32c tires if you want. I have around 16,000 miles on mine and still rolling fine - I took it for a grocery run yesterday. The downsides are the brakes (but brakes are cheap to upgrade) and weight, 28-30 pounds rolling weight. The entry-level MTB gears and derailleurs (Shimano) are solid. The frame, fork, wheels are if anything more durable than you'll find on most entry level road bikes.