I would love to live near the sea. Here, it would probably cost me fifty quid to get to it! I can walk outside, though and do, every day. It’s about as low cost as you can get, and will dry out soon and there will be bluebells and green leaves.
Audiobooks and music (on YouTube or the radio) Yoga with Adrienne (or Sarah Beth. She spams you a bit, though, if you register). Podcasts and blogs on YouTube (watch the ads, and people get paid. Win-win!)
Reading (library, if you like. I think ours is open from 2.47pm to 3.01 on Fridays every other full moon, or something, so I tend to borrow from friends or a swap, or read books I already own again)
Catching up with friends (can save money if you take turns hosting, and your heating can be off while you’re at theirs)
Naps. Naps are totally free. I adore naps. (Because. Children). Also, early nights.
Decluttering. I find clear, uncluttered spaces pleasing and relaxing, and being broke has definitely helped a lot! I may have been buying more tat that was good for me! I have kept notes of all the things I’ve wanted and haven’t bought because I am skint, and I haven’t added much, it’s pretty much stayed the same. Ironically, there are several hundred pounds-worth of plants and few thousand of sheds/greenhouse etc that I’m eagerly coveting, and I’m laughing at gardening being ‘free’ (of course, it can be low cost too. I just like spending money on it!) lots of local garden societies etc will do seed swaps and trade cuttings if you really need help to get started. (You need compost, unless you scrounge or make some)
Helping - Volunteering. Our local community centre does loads. Various coffee mornings (some free), litter picks, chatting with people who are struggling, a free youth club, and village resources, from posting letters to distributing whatever people need (they have resources from grants)
Last year we got some frogspawn from a local pond and watched the tadpoles grow into frogs (in a bucket. In the sitting room. DD loved it. We put them back where we got them from). Feeding the ducks (not with the frogs!) petting dogs you meet (is borrowmydoggy free?)
Some things aren’t free (like say knitting or or pebble pictures) but if you were to ask on a local group for yarn and needles because you were on your uppers and wanted to keep busy, you’d be drowning in donations of yarn and needles, and there are tonnes of free patterns and tutorials online. Knit nights or groups are often super low cost, or free.
Learning. Again, not always free, but the library and t’inernet can get you started with learning about things - languages, singing, history, culture. Loads of stuff.
Bingo (diy at home) and quizzes like ding bats, for groups. Card games (well, cards cost money, but pennies and you can do so much with them)
Treasure hunts. There is nothing mine would rather do than follow daft clues around. Puzzles and crosswords are often available online. Shadow puppets.
Some crafts are either free, very low cost or the stuff can be easily obtained by asking if anyone has stuff they are gifting.