The term "life hacks" has become pretty popular over the last few years, and there are some sites out there that are literally dedicated to just posting these kinds of time/money/effort-saving tips and nothing else. Sometimes these "hacks" end up not being worth it, but sometimes they can genuinely be pretty brilliant.
My favorite tips are the ones that take something I've been familiar with all my life and then show me something totally new or unexpected with it. For instance, how about this list of various common household items that the majority of us have probably never realized we were using incorrectly.
1. You can peel a hard-boiled egg without peeling the whole shell. Just break the top and bottom off, then blow into the egg as seen below.