macramé was mentioned but I want to mention that if you see it you will think maybe it is hard but its literally doing the knot where you take two strings and loop them around each other so pulling the string just makes it tigheter. Also you can make a sling from it sized to fit something like a tennis ball or any other ball you have around and then you can take it to a tennis court (parks around me tend to have them) and then practice slinging it. Big plus to do with a dog.

From a similar post recently:

Inexpensive, and little setup, with no steep learning curve?

Off the top of my head:

• singing
• drawing
• playing a tin whistle
• dorodango
• dexterity games (card flourishes, astrojax, yoyo, pen spinning, etc.)
• reading
• kumihimo
• customising things with paint markers
• yoga
• whetstoning
• writing (prose or poetry)
• journaling/journalism
• cross stitch/embroidery
• jelqing
• rock/object balancing
• meditation
• knife throwing
• macramé (using beading floss)
• playing the spoons
• whittling
• eating
• scrimshaw
• nålbinding
• henna tattooing
• primping
• cloudgazing
• looking at fucking everything through a high mag loupe
• tarot divination
• contact juggling
• kefir making
• key duplication by hand
• sleeping
• hiking
• floccinaucinihilipilification
• origami
• talking to nearby friendly looking strangers
• polishing
• cleaning
• caligraphy
• drugless hallucination
• soapbox public speaking
• zen gardening
• guerilla gardening
• pitch ear training
• 'easter egg' hiding
• local botanical/ecological studies
• flint knapping
• home/interior design (as long as you don't actually buy anything)
• knolling
• marble running
• solo RPGs like 'Alone Among The Stars' (okay this one wasn't technically off the top of my head. I couldn't remember the name, so I looked it up.)

Hiking/going for walks, sketching, reading (public domain books are free at project gutenberg, libraries are free), watching shows/movies (again, libraries offer access to this locally and through apps like Hoopla, Kanopy, etc. and there's free streaming off Pluto.tv, Shout.tv, Tubi, etc), music (again, libraries or free streaming), body weight exercises and cardio don't require a gym.

Might add more later...

• Building your own transit lines on a map. I do it on the website called metrodreamin sometimes. Very fun!
• Writing policy docs/bylaws/rules for literally anything. Can be a country, a city, a coop, some fictional entity, anything! Completely free. When I actually write stuff, it helps me understand my own beliefs and opinions much more clearly. Bad opinions become a lot easier to spot when you write them out. Stretching these "rules" to their logical extremes is so fun too! Helps you understand holes in your opinions/limitations. I remember writing down my ethical framework. So fun!
• Programming. It's free. You can play around n do whatever.
• Reading porn. Written porn vs audio-visual porn is such a massive massive difference. Written porn often has something that audio visual porn doesn't - emotions. Also, the setup for written stories is so much cooler than audio visual stuff.

Pottery. Clay is free. Water comes from the sky. If you have like a bucket or something, you're set. You can fire it in an oven you make yourself. Out of clay. For free. Clay is great. Highly recommended. Ask your physician if clay is right for you.

Also, be careful where you source your clay from. You don't want to get Lynks disease.

Sneezing.

I started learning the drums before I got My drums. You can learn the theory and practice beats on the objects around you. That's the cool thing about drumming: everything in the universe is technically a drum!

Check out your local library! They have books of course, which can open up all sorts of new hobbies, but modern libraries also can have computers, free classes, workshop and maker spaces, tool borrowing, and sometimes even video games and the like. My local one even has free tickets to museums and the zoo!

If you want something free/cheap as hell, take up drawing. You don't need fancy art supplies, just a pencil and paper. Look up proper drawing classes and books and get awesome at sketches!

TTRPGs like GURPS or OpenD6 for free group activities. All you need are pencil/paper/notes app and 3 6-sided dice, and you can roll them with an app or on plenty of webapps (dddice.com is a good one for shared gaming). A lot more to learn than playing cards or board games, but much more fun than a typical game night, something the group can talk about all week between sessions.

I looove to do Geocaching. You combine hiking with Geocaching and it's a game changer

gooning

As long as you have a computer you can code, write, or digitally create nearly anything you want.

Origami, lots of videos and diagrams for free online, paper is cheap and if you want to go even cheaper you can specialise on scrap paper.

Free

• Hiking
• Bird watching
• Volunteering

Low cost (some equipment required)

• Hunting
• Fishing
• Cycling
• Chess

Maybe not completely free but ukuleles are really cheap, easy and fun.

Singing is completely free, I'm sure you can find tutorials online.

In many places you have free outdoor gyms that let you practice calisthenics, 0 equipment needed.

If you have a smartphone photography, filming or stop motion animation can be done for free with open source software.

Last but no least, if you find some thread you can make a balearic slingshot and practice outside (or inside with ping pong balls). There are competitions and everything. Making them is fun in itself.

This is how you make one and how you use it. You can look for other videos on how to make one. Different materials can be used. It takes a bit of practice but it's a fun, manual work. I can make one in about 2h.

Chess. You can try Lichess, a free (and open source) website/app to play chess. There's countless of videos and tutorials on the internet about chess.

I haven't seen Cooking, Baking and even Gardening on the list.
These are hobbies that saved you serious amount of $$.
Making food from scratch is always cheaper and healthier.
If you don't have much space you can have a tiny vertical garden (pallet) or just a few spiceso n your counter.
And technically growing weed to smoke is gardening and also saves money (tho I don't know first hand, I don't partake).

Edit: forgot about: hand sewing and hand embroidery, crochet and knitting. You can fix up clothes so they last longer - and you can spruce up existing clothes also.

Hiking can be nearly free especially on beginner trails that don’t require special equipment

Writing is something I hated in school but as I’ve gotten older it can be fun to kinda play god with peoples lives.

Cooking isn’t free but could actually save you money if you eat out a lot.

Geocaching

Being in a city, there could be lots of caches near you.