I think the best $3 investment I’ve ever made is the red LED party bulb I got at Walmart a few years back. 

At night I put it in the light fixture next to my bed and kill all the other lights. The dim red light really helps to make me feel relaxed and sleepy. I find it also is a major mood booster – it’s hard to be blue much less depressed under red light. 

It’s bright enough to read and see things in my bedroom so I don’t trip although color rendition is nearly non existent.