Investing is often a frustrating topic for working people who don’t have a lot of extra money to set aside. Wealthy people may grow their incomes by investing in various opportunities, but few of those options are available to people who don’t already have millions of dollars.

That doesn’t mean you should stay away from all types of investing, though. Most people find that these three investment opportunities help them make enough money to fund their retirements.

Employer 401(k) Contributions

According to the Bureau of Labor Statistics, about 89 percent of full-time employees at Fortune 500 companies have access to employer-sponsored retirement plans, such as matching employee 401(k) contributions. Some employees, however, don’t take advantage of matching contributions.

Many employers match half of your contribution, up to 6 percent of your salary. If you earn $50,000 a year, you can contribute $3,000 and get an extra $1,500 from your employer.

If you don’t participate in your company’s 401(k) program, you’re missing an important benefit that could help fund your retirement.

Traditional IRA or Roth IRA

Starting an IRA (Individual Retirement Plan) or Roth IRA account gives you opportunities to save for retirement with or without employer contributions. There are several types of IRAs, but traditional and Roth are the most popular options.

The government sets contribution limits, letting you invest up to a certain amount each year. The 2015 contribution limit for traditional and Roth IRAs is $5,500. If you’re 50 or older, you can contribute up to $6,500. Sites like Scottrade will also give you incentives for rolling over a 401(k) into an IRA.

To get the most out of your IRA, you should contribute as much as possible every year. You make more money by opening an account sooner, since earnings get put back into the account where they can grow exponentially.

Mutual Funds and Stocks

Investing in stocks and mutual funds doesn’t cost as much money as you might think. Still, the rewards are often significant.

Cautious investors should focus on mutual funds that contain stocks from diverse industries like biotechnology, pharmaceuticals and energy. Diversified funds are more likely to grow slowly while avoiding the frequent ups and downs experienced by stocks in specific industries.

If you’re willing to take a bigger risk, you may want to invest in individual stocks. Keep in mind, though, that there isn’t much protection when you buy stock in one company. Even if you don’t purchase a mutual fund, it makes sense to diversify your investments to avoid market fluctuations. If you want to try it out, sites like OptionsHouse will allow you to trade for free for 60 days.

Investing always carries some level of risk. Studies show, however, that these three options are fairly stable, even for working-class people who can’t afford to waste their money. If you aren’t sure which options are right for you, speak with a financial planner to get expert advice.