Aldi have just had one of their bicycle-related sales. Among the bargains was an LED lights set - front and rear for $9.99.
The bonus is that batteries ARE included - 6xAAA batteries. A 4-pack of these is $3. So that's $4.50 worth of free batteries.
All that maths means that really the front and back lights for your bike are just $5.49. That's loose change.
I'm continually impressed with how cheap it is to cycle.