One of the most fun things to do that is also completely free is stargazing. If you live in a light-polluted area, you may have to drive a little bit out of town to get to a good spot. But it's worth seeing the stars in all their glory.
Parks are fantastic places to have fun without spending much money. You can do many things at the park: sit and read, watch other people play, relax, have a picnic, and more.
Flea market is a great place to find some fun things to do without spending a lot of money. You never know what you'll find, and it's always fun to browse and see what's available.
Many communities offer free events throughout the year. So if you're looking for some fun things to do, check out what's happening in your city. By getting involved with your community, you get to have fun and meet new people.
If you want to get back into learning, it's never too late to try something new. Maybe it was a skill you wanted to learn but never got the chance. If it's something you want to try or are interested in, you should just do it!
If you're looking for fun things to do that also give back to the community, consider becoming a volunteer. Many organizations always need help, and you'll likely find one that's a good fit for you.