One of the easiest ways to save money is to buy in bulk. On the surface it’s more expensive because you’re of course paying for things that you don’t immediately need but if you’re certain you’re ultimately going to use something and you’re paying less per item, there’s no reason to pass up bulk savings.
A great thing to buy in bulk is batteries. If you store in the back of freezer they’ll definitely last you a good while and you can be all but certain that the time is going to come when you’ll need a couple of AAA batteries. When you’re buying them in bulk you can usually get them for about $0.40 each, which is way better than buying them at around $1/ea when you’re only buying six at a time. At the moment, I have about two dozen of each of the common types and at least a handful of the weirdos (D, 9 Volt, etc). Anyway, buying in bulk is where it’s at so when you see a great deal snap it up!