Runelight Token

Runelight Tokens are a common way to navigate those areas of the world that are cast in shadow. They operate on a simple magical principle: pay, and get light.
Runelight tokens are thick discs about the diameter of a small adult hand. There is a slot in one side. Insert a coin, and the token will light up with a subtle, non-offensive magical light, bright enough to see but not so bright that one risks attracting a lot of negative attention.
They are cheap to buy, and like most such things can get rather expensive to maintain.