6 simple ways to invest your money that you probably haven't thought of, according to financial experts

Misty Lynch, lead financial consultant at John Hancock, told Business Insider that collections of all sorts can become clever investments.

"As an '80s child, I owned several valuable investments before I even knew what that word meant," Lynch said. "Sadly, my toys often received bad haircuts and random attacks from our dog. If I had kept them in the box they could have helped put my own kids through college."

Retro toys can have increasing, and even surprising, value over the years. The original Xavier Roberts Cabbage Patch doll that Lynch said she owned could be worth hundreds of dollars today, according to the Williamson Daily News. And toys aren't the only item geared toward kids that have shown collectible value.

Fueled by countless movies revolving around superheros, villains, and anti-heros, and the increasing popularity of events like Comic Con, the comic book market continues to rise in value. As Wired reported, books that have originally sold for less than a dollar can now sell for hundreds of thousands of dollars.

Vincent Zurzolo, the co-owner of New York's Metropolis Comics, told Business Insider that he has made thousands of dollars in the blink of an eye through his collection of self-proclaimed "kiddie fare." Zurzolo said that a comic book can jump in value from a few dollars to $100 and that anyone can benefit — if they do their homework.

Zurzolo's steps to take part in the trend include studying the market trends and looking at new movies slated to come out, setting a budget for yourself, and figuring out if you're trying to hold onto books for a short or long period of time.

Lynch added that other valuable collections can include musical instruments or even bottles of wine.

Author Sharon Marchisello said that before even thinking about investing in anything else, people need to pay down their own debt.

"It's 100% risk free, and the return is guaranteed," Marchisello, who wrote the book "Live Well, Grow Wealth" based on her own financial experiences, told Business Insider about debt payments. "Because consumer interest is usually higher than investment interest, you're getting a higher rate of return than you would by putting your money into another investment vehicle."

And with Americans' total household debt hitting an all-time high of $13 trillion last year, according to the New York Fed, debt payoff is an investment that applies to virtually everyone.

Marchisello said that the best investment a person can make is to nip their debt in the bud now.

"Eventually, you'll free up cash flow that can be used toward other, more conventional investments," she said.

A lot of people think they'll never need renter's insurance or that it's too expensive, when in reality it costs about the same as a bottle of wine a month (or less).

Braden Davis, the chief insurance officer for Jetty Insurance, told Business Insider that the cost of renter's insurance can even dip as low as $5 per month and is quick and easy to sign up for.

"Most importantly, it can cover a lot more than you think," Davis said. "From everyday occurrences like shattered cell phones and broken laptops, to disasters like fire and theft."

According to Forbes, most renters don't have renter's insurance. Typically, the insurance covers personal property, temporary living expenses, and personal liability — including if you're ever robbed, or if flooding or fire causes your stuff to be ruined.

"It's a great way to get peace of mind and invest in your future self," Davis said.

Dock David Treece, a financial planning expert and senior investments analyst for Fit Small Business, suggested that advanced industry training is a great investment to make in yourself that can pay off in the long haul.

"When people think of investing, they often think of stocks, bonds or mutual funds," he said. "But training specific to your industry or role can be a great investment."

And he's not wrong.

According to Glassdoor, having certain accolades such as Google certifications or project management certifications can make a candidate more desirable to a job recruiter. In addition, already having a job and going through additional training or earning certifications could be compelling leverage to put toward a raise or promotion.

"This training can grow your future earning capacity and help you build retirement savings faster," Treece said.

While spending money on health insurance, a gym membership, a trip to the dentist, or a meal plan might not seem like a form of investment, Jennifer McDermott, a consumer advocate for the personal finance comparison website Finder, would have to disagree.

According to a study Finder conducted, Americans were forced to borrow $6.12 billions for medical expenses in 2017. McDermott said that by incorporating regular good-health practices into a routine, like regular visits to the dentist, annual visits to a general physician, and attending a gym, people will save money down the line.

"While an investment in things such as gyms and special diets are often associated with vanity, they can actually prevent high-priced health issues," she said.