@mhoye Stainless steel kitchen containers.
Cleanup is easy, contents don't spoil nearly as fast compared to plastic-only containers, and every part is replaceable. Flour, sugar, baking soda, all the core components sit comfortably inside.
Like, stainless steel *everything* in the kitchen is also good. Pans, tongs, measuring spoons, jiggers, etc. So many places sell cheap plastic crap that's a PITA to maintain, that the extra dollar or two makes a world of difference every day.
Same with a bag of clothespins, kind of like your binder clip suggestion but less effective.
Outside the kitchen? A power screwdriver. Just...why, *why* did I not buy this sooner? *Why* did I hate my hands so much, for so long?
A roll of tac-tape is also a godsend for securing all the things (cables, bundles, books, etc). It's everywhere, but I'm still on my first roll ever because it's infinitely reusable.