Outside of one's job and daily routines, many people indulge in hobbies for relaxation or pleasure. "There are so many levels of expectations [in everyday life], that to find something that is just for you to enjoy-one can imagine that that would be useful," said Carol A. Bernstein, a psychiatry professor at the New York University School of Medicine, according to Wall Street Journal.

Some hobbies may be more expensive to maintain than others, such as photography or golf, but there are other leisure activities you can do that can also be fulfilling and enriching without having to spend a lot of money.

1. Reading. There is enough evidence to prove that reading makes you smarter, according to The Guardian, so, it's no surprise many successful people have this hobby.

To save money, check out local libraries for books you can borrow for free. You don't have to worry about the cash nor space if you only borrow and return on time. You will need to get a library card - that is, as long as you don't intend to become a book collector! The latter may be another distinctive, but slightly more expensive hobby altogether.

If you do want your own copies, but aren't particular about book collections, you could invest in a good reading tablet one time and just download books for a fraction of the cost online.

2. Coloring. As latest the sales report shows, adults are getting into this childhood hobby for its stress-relieving benefits. You don't have to own the best materials to start coloring. You can purchase coloring supplies on the cheap at Walmart with its back-to-school specials.

For a list of some new and best-selling adult coloring books, check out this article from HNGN.

You may not even need to buy a book. You can print off illustrations on the internet, such as these free sheets from Pinterest users.

3. Learning a new language. Being bilingual makes you smarter and enhances the brain's executive function, the experts say. "Bilinguals have to switch languages quite often - you may talk to your father in one language and to your mother in another language," said Albert Costa, a researcher at the University of Pompeu Fabra in Spain, according to The New York Times. "It requires keeping track of changes around you in the same way that we monitor our surroundings when driving."

You can start by learning the basics of Spanish, French, German or Italian for free with a DuoLingo app.

4. Becoming a volunteer. Using your spare hours to help others is a rewarding experience because you know you're making a difference on the lives of other people. Check out local communities, city hall and charity organizations for any slots for volunteers. You can help out at animal shelters, a soup kitchen or hospitals and clinics.

5. Learning to play a musical instrument. Music shapes your mental and creative development, as well as your fine motor skills, the same way sports and arts do. Scientifically, music makes the brain's corpus callosum stronger, which helps with memory and problem solving, according to Upworthy.

Of course, you will need to shell out cash for the instruments, but you can purchase used ones on Craigslist, eBay or Amazon to save on money. For the lessons, you can check community colleges, as some offer short sessions to those who won't need classes for course credits. Ideally, you can also self-teach with the help of YouTube, as there are tons of tutorials for this.