Having a night light can be a great convenience, letting you find your way around your home at night without turning on the lights. Many kids also find it comforting to have some light when they fall asleep. You can get motion activated night lights, switch operated ones or photosensitive ones that only turn on when it is dark. The type you choose will depend on what you want to use it for.
One common problem with cheaper night lights is overheating. When inferior materials are used, or when the night light is poorly built, they do pose a fire hazard, so it is worth shopping around a bit, making sure to read reviews.
While the price can vary greatly, you don’t need to spend a lot on your nightlights, but be wary of those that have ridiculously low prices. It is probably best to go for a middle of the road price that will be safe and meet your needs.