Lights are critical for riding at night. An effective rear blinkie can be bought inexpensively. They are visible for quite some distance ahead. You can get a front blinkie (a white light). These are good for letting drivers know that you are there. But a strong headlight is necessary for dark areas so you can see things like turns in the road, animals, pedestrians, potholes, tree limbs etc. Unfortunately, strong headlights are relatively expensive. Still they are a bunch cheaper than a serious injury.