Play Games Cheaper
Up to 70% off select toys and games in Amazon country. One of the things on sale is a bunch of glow-in-the-dark stars to put on the ceiling, the Great Explorations Celestial Super Kits - Wonder Stars Super Kit.

Loved this Amazon reviewer's idea of turning them into a parenting tool:

I got these thinking they might help my 3 year old in the dark at night. I was going to put them all up at once, when I realized she could earn them. For every night she goes to bed without giving us the run around, she earns one star. For every nap she takes, she earns two. It works a good chunk of the time.