Go here:
http://www.performancebike.com/shop/....cfm?SKU=14870
Performance Bike has the NightHawk Viper for $20. It has a rechargeable bottle cage battery and a 5 watt bulb that gives 4hrs of light. For $10 more, you can buy a 10 watt bulb to swap out. Since you're riding in the winter, your speeds won't be super fast when it's dark and 10 watts (in my experience( is plenty for about 15mph or so. The assembly can be taken pretty fast for day rides but putting it back on takes an extra minute (I quickly replaced the zip ties w/ velcro straps). I LOVE this setup! Especially for $30.
Go to Wal-Mart and buy the little rear flashers for kids' bikes at their Ray-o-Vac battery stand. They're orange w/ a blue mount, but only set you back $4 instead of $10+ and they run on 2 AAA.
I'm quite visible at night (and morning) for only $35! Yay me!