A few things you could probably get for $1, but would be better if bought in bulk:
A permanent marker, a package of labels.
Combined, you can reuse your Amazon boxes as storage boxes. Labels aren't necessary, but black text on a white background is easier to read from a distance.
Box cutter knife/utility knife.
Can be used to cut holes in Amazon boxes for pets to play in. Or, simply keep them but the front door so you can open packages right away.
Hook-and-loop (Velcro) ties for wires.
Can be used to tidy up the wires behind your desk, or for charging cables when traveling.
Dish soap (without degreaser)/baby shampoo.
Aside from their original purposes, these can both be used to clean glass before applying a permanent tint (or just to clean glass normally) or to wash your car (degreasers can wear away at your clear coat over time.) Both can be found at the dollar store.
Colgate regular toothpaste. (If you don't have tooth sensitivity)
You don't need colgate total. You should still use an electric toothbrush. You should not use the cheap off-brand toothpaste. You should also floss.
Jellyfin/Subsonic/Plex Server
If you have a digital library (movies, shows, music) and an old computer/laptop/raspberry pi, you can put one of these three programs on it and host your own, personal, Netflix/Spotify for free with no ads. You only need to pay for electricity. You need to learn a bit to set it all up, but once it's done it's very set-and-forget. You'll also need to buy or find your new media online (or rip it from a disk), which can be a big change for some.
Something else that has a low barrier to entry: origami. Learn how to make a square from any sheet of paper, then learn how to make the traditional paper crane. All you need is any piece of paper and scissors (to cut it into a square). If you enjoy making the crane, there's an endless amount of models to fold. The craft has exponentially taken off in the last few decades, just do a little searching.
A vpn subscription over 3 years or split the cost with a friend, it comes to about 1 something a month. Cheaper than those shitty subscription services.
P51 Military Can Openers: I have several of these. I have one on a tiny magnet attached to my kitchen door should I ever need it. Works about as well as any other can opener. Easy to slip in a drawer, keychain, car, exct.
Mason Jar plastic reusable lids: great for storage as well as meal prep. I have a lot of mason jars and these are awesome.