A high quality mechanical pencil that takes girthy lead. I use a staedtler 925 2mm and it's absolutely wonderful for taking notes and writing and has served me through high school, college, and work. It writes similar to a regular wood pencil but sharpening is optional

Oestrogen (joking but also serious)

On a more serious note, a raspberry pi to run pihole and gobble up all the ads for all devices on my home network

$20 can buy many peanuts.

I'm surprised I did not think of mentioning it next to the Preppy fountain pen I already mentioned but a reading lamp! This one is 15-18€ clip-on. It's USB-C (I would prefer standard batteries if there was a model so it doesn't got to waste one the battery is dead). It's lightweight and the brightness (as well as its temp) can be adjusted.

Worth every single cent, imho. I find it so useful that I have purchased two, just in case I need to recharge one.

1L water bottle, especially if it’s insulated. Keeps your drink cool, but also makes it so I don’t have to get up to get more drinks when I run out.

We had some in a car during a trip to Wonderland during the summer. A Gatorade bottle was disgustingly hot while the insulated bottles still had ice in them.

5/7 would recommend

A 10-foot USB cable. Most people use whatever's packed in with their electronics, and it's pretty rare to get anything longer than 6 feet. Having the extra length is really nice in many situations.

It's also one of my go-to inexpensive gifts or part of a care package for someone in the hospital. The extra length there is often the difference between being able to use a device while it's charging or not.

Wool socks if it's winter and/or you live in a cold climate.

Converting $20 to local currency, I'd probably go with this:

This is so-called "Liubao Tea", a kissing cousin to pu'er tea. I did a review of my first batch(es) and it has rapidly (literally with one round of brews) reached the top of my circulation in teas.

The depicted tea is one aged from 1991 (the one I reviewed was tea stems from 2003) and is of one of the higher grades. A 100g package will set you back about $15 or so at today's exchange rate. 100g is about 15-20 servings, and each serving can be brewed multiple times (even my tea stems can be brewed four times without loss of flavour), so it's quite the bargain.

Save it for a time when you really need something warm, rich, and comforting. It will last forever as long as you store it in a cool, dry, dark space. And personally I think it's a bargain at 15 bucks.

Pet jumping spider.

Honestly 10 star pet. They eat a small bug every other day or so. They look adorable. They will recognize and react to you, and you can even train them to accept handling. They come in a wide variety of colors.

Downsides are that you'll probably end up getting more than one (do NOT co-hab them!), or that they only live for 1-3 years. If you enjoy having the spider though, you can look into other arthropods like tarantulas, or vinegaroons (which look scary, but are harmless and have very sweet dispositions).

Bidet attachment.

2kg of cookies

Fluffy stuffed animal. If I didn't have a couple stuffed kitties to hug I probably would have killed myself already. Nice to have something to pretend loves you

If you use your phone a lot (or if your battery is old and you haven't replaced it), a power bank is very useful.

A reputable powerbank (such as those from Anker) cost just under $20 USD for 10,000 MAH

Mini Swiss army knife. I don't know how to live life without this on my keychain

A beard trimmer. Shaving sucks and irritates my skin, plus I look like a baby without facial hair. But that's only one benefit.

I have been using a beard trimmer to cut my own hair for the last 10 years which has saved me probably $2000 worth of haircuts (estimating a $25 haircut + tip every 2 months). Not to mention saving about 1 hour waiting at the barber every time. I only messed up once and had to do a buzz cut.

Not luxury, but I keep a small AAA flashlight with me nearly all the time.

Easier to handle and faster to use than a phone light. Also doesn't use phone battery. I clip it on my hat if I need both hands like taking out the trash.

I have an Olight i3T but I would try out the i3T 2. More lumens and better battery efficency.