Ask HN: Your most useful purchase of under $100 in 2018?

$20 foam roller. As someone who lifts weights, runs long distance, but also sits at a desk for 8+ hours a day, my body gets so incredibly tight by the end of the day. As soon as I get home I spend 20-30 minutes working on mobility from my neck down to my ankles. The foam roller helps a lot with that. It's painful but I feel so much better after.

$25 RTL-SDR dongle to sate intellectual curiosity about radio

$5 / mo // $ 60 / yr digital ocean droplets for intellectual curiosity about web dev

Not exactly within budget but ~$400 gym membership (from Costco.. so, factor in the amortized cost of that, too, I guess) for 24 hr fitness for 2 years - going to the gym has been a HUGE game-changer for me. Never really did it before with any discipline, and already within 3 months there have been great dividends for me. I'm much stronger than I was just 3 months ago. Much less anxious and stuff too.

I bought a water flossing machine. I've been flossing for more than a year, but there were always bits of my gums that stayed kind of sensitive. According to my dentist it was "possible to do it right, but hard", which I took to mean I was bad at flossing. Now I floss in the evening after dinner with regular floss and use the water flosser twice a day. Works like a charm, I would have gotten one ages ago if I knew they existed and worked this well.

$85 cordless impact driver (Ryobi) has been my new favorite tool by far. It doesn't do everything a standard drill can do (i.e. drill...) but it is far superior for driving stubborn screws and bolts in and out, especially when they are beginning to strip! It is easier to hold since you do not need to counter the torque continuously like you do with a regular drill.

Plus it makes a fun hammering noise which makes me feel like I am doing something important.

Paper to print my resume out. Got my first job!

A minimal laptop bag (Tomtoc). Switching from the big Swissgear backpack forced me to stop lugging multiple devices, dongles, keyboards, etc. Better for my back and better for my focus.

A (under $50 refurb) Apple Magic Keyboard 2. I was always struggling with muscle memory on different keyboard layouts so having something that's 95% identical to my MBP keyboard helped a lot.

Linode $5/month servers. Couldn't be happier with them as a place to park all those little sites for friends and side projects, mostly running Wordpress.

A vertical mouse for roughly 20 bucks. I had developed a strange tremor in my hand, so I decided to change the way I hold my mouse. Found the vertical mouse, which immediately made the tremor disappear. The mouse is bulky and ugly, but it took about two minutes to get used to and seems to be much more ergonomic.

A 90$ HP 22" monitor to use side-by-side with my 15" laptop display. The quality is a bit lower than the laptop display but having more space and a bigger display is such a blessing for my eyes and my productivity.

$90 8qt Instant Pot

It's dramatically reduced the number of times I eat out for convenience rather than enjoyment. It's larger than I need but perfect for bulk cooking/meal prep.

This reminds me of the Tim Ferris question he asks many of his guests.

I think my purchase would be a $20 yellow led light that does not have blue light. I use it for reading before bed.

Kombucha mother for $15. Now I can homebrew and enjoy Kombucha, a fizzy, sweet, low caloric, high probiotic beverage while coding.

$40 hhkb hasu usb controller

It allows you to flash firmware with your own keymaps to your hhkb.

It's a great buy if you already have an hhkb.

Paid tutorial. Much better than to put all the information in the right order from random places on the net.

Coffee maker! My daily morning coffee now costs me pennies and I can enjoy it in bed.

$20 Red Copper Flipwich Stovetop Panini & Sandwich Maker

https://www.bulbhead.com/products/red-copper-flipwich

It wasn't in 2018, but a couple or three years ago, I bought a brand new unlocked Android smartphone for well under $100, and it did everything I formerly used my Nexus for.

The new kindle paperwhite 2018, it was 85€ instead of 130€ around black friday. Now I can read all my tech and programming books I buy from bundles or get on PacktPub.

Most recently, a blender bottle for any beverage requiring mixing, such as a protein drink. $10 to $20. I got one with a ball that gets dropped in the bottle.

If you drink tea, a $30 davidstea 32oz loose tea steeper with a bottom dispenser. I love this thing.

I just bought a monthly subscription for a Mac Postgres client called SQL Pro for Postgres. After wrestling with PgAdmin 3 and 4, I threw in the towel and paid for a proper client. It’s 5.99 a month and as much as I hate rent-seeking, it allows me to try the software before paying the 139$ lifetime license.

Sadly, probably my Amazon Echo!

buy $100 worth of udemy courses when they are on sale

Adopting a pet.

- Sauna ticket