This one's kind of a no-brainer but it takes some self-control. This one rule has literally saved me tens of thousands of dollars over the years, but I cannot tell you how often I see family and friends ignoring this simple rule just to get something immediately rather than waiting an extra few days. It's a pretty safe bet that unless something is literally one-of-a-kind, like a precious painting or some other unique creation then it can be found somewhere on sale.

Shop online and you'll more than likely find what you need cheaper even with shipping. With some luck you might exceed a minimum purchase threshold that even saves you shipping charges. Add an item you absolutely need and will use to bump you up to free shipping whenever it makes sense, the shipping you'll save is like a discount right off the top of the extra item(s).