I try and save money doing the simplest things that require very little effort. For example, turning off lights in a room I'm not in, renting books from a public library versus purchasing them unless it is reference material I know I'll look at multiple times. Honestly, how often do you pick up a book that your read more than a couple of times?
Recently, I've been going through my house and replacing light bulbs with the more power efficient bulbs. The intial cost is a lot more, but I suppose if the energy and replacement costs are as good as they say, it will more than make up the difference. I've also increased the amount of insulation in the crawl spaces in my house as well as wrap my water heater in a thermal blanket.
I think those are all the ones I can think of off the top of my head.

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