Investing money into mental and physical health makes us feel better and ultimately happier while also making us more productive and creative so we can make even more money - that's a double win. Let's explore those investment options starting from one-time purchases and continuing with activities that require recurring payments. I will give you insights into some things I've already tried and explore activities I might pursue shortly.
One of the simplest ways to invest in physical health with a single payment is to create a basic home workout setup. In my previous apartment, I had a pull-up bar with dip handles and a yoga mat. It cost around 100$ and was enough to do 15-20 minute workouts. Add a few kettlebells into the mix, and you will get a solid setup to train your entire body.
Another obvious investment is renting or buying a house or apartment in a location that will provide clean air and options for a healthy lifestyle. In the context of your city, you can try to escape places close to high-traffic areas or toxic factories. Also, if your house is in a neighborhood you don't want to stroll through is less chance you will go out often, and walking daily, is one of the easiest things you can do to help your health.
While I haven't tried therapy myself yet, people usually get improvement in their mental space from consistent work with a good therapist. It's worth exploring because almost everyone has demons that hold them back. Another thing you can do on a semi-weekly basis is to go to SPA, sauna, or massage. While I don't usually get much from massages, saunas make me calmer. Eating right and getting enough nutrients have a significant effect on health. Investing in having a comfortable setup for cooking and buying quality foods and supplements could be the first step. If it's available in your city, you can get some healthy food-prep service or go as far as having a private chef if you are rich, I'm not quite there yet.
I'm not doing yoga actively now, but during lockdowns, I've been consistent with the practice, and it's a great way to add some piece of mind while making the body strong and flexible. While I did most of my yoga at home, going to classes helped with having prolonged, more focused sessions. Because of a group thing, you don't want to give up and walk away while everyone else is trying their best in the same room.
The next obvious choice is to have workouts with a couch in a group setting. Gym sessions with a knowledgeable couch will make you more accountable while improving the quality of your sessions. I don't have a gym couch since I don't have a problem with discipline in this area, and I like the flexibility of going there at different parts of the day based on a given day's schedule. But I had a couch in the swimming pool, and he made workouts more fun while improving my swimming technique and endurance. I would highly recommend giving swimming a try because it's not only great for your whole body, but it also clears your mind very well, and you will feel great after a swimming session.
Going into some kind-of nature is proven to have positive effects on your well-being. The first thing you can do is to live in a place that provides fast access to the kind of nature you enjoy. It could be a seaside place, a city with hills or mountains to hike nearby, or at least a neighborhood with good parks. If moving out of a big city isn't an option for you right now, you can explore trips to the neighboring nature spots in the evenings, take vacations to the seaside in the summer, and ski places in winter. Also, you might try prolonged trips to beautiful places as a digital nomad.
Doing what you like will make you much happier. If you hate your current career and have money to deploy, start investing in getting into the type of work you enjoy. Buy courses, mentorship, or time by working less at your current job or business. If you have a lucrative job that makes sense for earning money at the moment, it might worth continue working there, but taking steps towards a better career will always be worth it.
Having meaningful social interactions and relations will make you happy. If you are single and want quality romantic relationships, invest in that area by getting in shape or going to places where you are most likely to meet the opposite sex. To find friends or a community, you can start exploring group activities ranging from CrossFit or JiuJitsy and language classes or board games events.
If you don't like meditation, you might explore playing musical instruments as an engaging pursuit allowing you to enter a good mental state. I've tried guitar and singing lessons, and I recommend trying singing first because you might have a good range that will allow you to sign songs you like.