The 9 smartest things to do with your money in your 20s

"Pay yourself first," says Meaney. "It's one of the smartest pieces of advice you can get." This means, first and foremost, contribute to your 401(k) if your employer offers one, and take full advantage of your company's 401(k) match program — which is essentially free money — if it has one.

Also, get in the habit of upping your contribution on a consistent basis — just 0.5% of an increase can make a difference — either once a year or every time you get a raise. Check online to see if you can set up "auto-increase," which will automatically increase your contributions every year.

Another retirement account worth investing in is a Roth IRA, says Meaney. Contributions to this type of fund are taxed when they're made, so you can withdraw the contributions and earnings tax-free once you reach age 59 1/2.

There's an income cap ($116,000 a year or less for individuals; $183,000 or less for married couples filing jointly), so they're particularly well-suited to younger people.

"Typically, when you're starting off in the workforce, you have an income level that would not disqualify you from doing a Roth IRA, which is a very attractive retirement savings vehicle," explains Meaney.

Cash flow is one of the most important things to be aware of, especially in your 20s, Meaney tells us: "You've got to know where your money is going and you've got to make sure that more money is not going out than is coming in."

This means sitting down to craft a budget. Creating a budget does not have to be the daunting process that people make it out to be; in fact, managing your money can be quite simple with the proper resources and attitude. For ideas, take a look at the insight offered by 14 regular people who keep diligent budgets.

There are also many free budgeting apps to help you categorize and monitor your monthly and annual spending.

Monitoring cash flow and goal setting are the two most important concepts to master as a 20-something, Meaney emphasizes.

"You can never save enough," he says. "There will always be something to apply that towards. The key is that you set goals and prioritize the things that you want and might want down the road." This may be a vacation, a down payment on a home, or graduate school.

"Get an idea of what you would have to save, how long you would have to save for, and at what rate of return you might need your investments to grow to reach those goals," advises Meaney, and then start putting away money — ideally, 20% of your annual salary.

It may be helpful to set up multiple savings accounts in order to save for specific purchases. Check the online interface of your bank and see if it will allow you to create sub-savings accounts.

As tempting as it may be to save a bit of money each year by foregoing insurance, that's one of the worst money mistakes you can make.

"If you are a renter, definitely get renter's insurance," says Meaney. In addition to covering break-ins or damage from a fire or severe weather, renter's insurance will cover you if your car is ever broken into. "Anything that is not part of your vehicle that is stolen from your car — golf clubs in your trunk, for example — is not covered by auto insurance," he explains. "Your renter's insurance on the other hand, will cover those items."

Auto, health, and disability insurance are three other must-haves, Meaney emphasizes. Check out this young adult's guide to affordable health insurance to get started.

"If you have additional cash flow, it makes sense to start building up some emergency cash reserves," says Meaney. While it's easy to dismiss the possibility of your car breaking down or a medical emergency, these are both valid scenarios that could quickly become expensive realities.

The amount of savings you need is highly personal, but a general rule is to have six months' worth of savings tucked away. Of course, you may need more or less depending on your situation.

If you're living in a city, using public transportation may be the cheaper option, but if you need a vehicle to get to and from work, resist the temptation to splurge on a sleek and shiny new car. Rather, buy used. Cars are a hugely depreciating asset, and you don't want to overspend on something that's not going to be worth much in a few years.

Meaney advises looking into slightly used vehicles: the two-year old, 40,000-mile options are his favorites. Check out Kelley Blue Book to get an idea of how much you should pay for a used car.

Another option is leasing a car. You can determine whether or not this is a good option for you by following this flow chart.

Invest in things that have value. While it may be hard to part with your cash, some things are worth spending money on, such as a nice interview suit or new experiences. Check out more smart purchases to make in your 20s.

Quality purchases don't necessarily mean big-ticket items; there are several everyday items to invest in that can pay for themselves in a short amount of time, such as a commuter bike or coffee maker.