Acorns represent the idea that something small can grow into something much bigger, and the Acorns personal finance app applies that concept to your money. Acorns opens an investment account for you and adds small amounts of money to it every time you use credit or debit cards by rounding up the purchase price and putting the extra into your account. It's a good mobile personal finance app for people who have put off investing for too long and need something convenient to help them get started. It's not the best investment strategy you could devise, but it's worth checking out if you want a little extra help taking control of your money.

Acorns has apps for iPhone, Android, and Web. It's designed as a mobile-first service. I tested the iPhone app for this review.

Pricing and Fees

Acorns charges $1 per month for its service for accounts with investments of less than $5,000. If your account balance is less than $1, you're charged all of it instead of a dollar. There's no minimum required. Accounts that contain $5,000 or more pay 0.25 percent per year of the daily balance in your account, charged monthly. The fee isn't terribly high, but it could end up causing you to lose money if you don't invest enough. University students with a valid .edu email address can use Acorns for free for four years from the date of registration. All the accounts are SIPC-insured up to $500,000 against fraud.

A dollar a month may not sound like much, but many otherpersonal finance apps are free. Other investing tools have different pricing structures, such as charging a flat fee per trade, which can easily be less than $10.

Acorns' fees are nearly identical to those charged by Stash Invest (Free at Apple.com) , another mobile investing app. For accounts with at least $1 but less than $5,000, Stash Invest charges $1 per month. Accounts with an average daily balance of $5,000 or greater are charged 0.25 percent per year or about 0.021 percent per month. Stash Invest aims to help people start investing quickly, but it doesn't help put away money the way Acorns does with its rounding up scheme.

Yet another app with an "invest your spare change" approach, Qapital (Free at Apple.com) , doesn't charge any fees at all. It puts your money into a savings account rather than an investment account, and the company takes a cut of the earnings, which is how it makes money. As with Acorns, Qapital has options to round up purchases and put the small change into your account. It also has more creative options for how you can contribute, such as adding a dollar to your savings whenever someone tweets at you.

How Acorns Works

To give Acorns a whirl, I walked through the setup process as far as I could go without actually opening an account. (I'm not in the market for a new investment account.) Then I asked the company to hook me up with a demo version so I could get the feel for the service without actually ponying up any of my own money.

During the signup and setup process, the app asks questions about net worth, annual income, investment goals, and so forth. A company representative explained to me that the app uses that information to recommend one of five portfolios for your investment, ranging from conservative to aggressive. It also asks for your age, financial goals, and risk tolerance. No matter what Acorns recommends, you can always change your portfolio at any time.

The app also encourages you to take a number of steps to get started with your investment. These steps include connecting a credit or debit card that you use for round-up contributions and adding a primary bank account that you can use to make bigger contributions (and, once you're making money, withdrawals). If you don't complete all the steps right away, you see reminders to do them every time you use the app or website.

From the app, you can manage which accounts are used for rounding up purchases, and you can adjust what it means to round up. By default, roundups go to the next whole dollar, so that if you charge $3.25 to your credit card, Acorns rounds up to $4 and put the additional 75 cents (of your money) into your investment account. When a purchase is an even dollar amount, Acorns adds $1. You can adjust the roundup number to whatever you want, though.

Security and Privacy

Is Acorns safe to use? I reached out to a company representative to get a bit more information than what's available on company's lengthy privacy statement, which is available online.

As mentioned, all the accounts are SIPC-insured. The site and apps use SSL encryption (256-bit) and bank-level security, meaning secure servers and security supported by McAfee. The representative also added that the company contacts customers about unusual account activity for protection against fraud, and never sells or rents customers' personal information.

Will Your Tree Grow?

I like that Acorns gives people who have put off investing an easy way to start, even if it's with very small amounts at first. It can satisfy the emotional need to stop slacking off with your money and start doing something. But there's no way it can replicate the advice of a personal financial planner, which may be what people who procrastinate about making decisions about their money really need. You'll want to examine the fees carefully, too, to make sure the amounts you're contributing are worth your while. It's also important to remember that an investment account is not a surefire thing, whereas an interest-yielding savings account (which Qapital uses) is. The difference, generally, is that investment accounts payout at a much higher rate, but you must be able to tolerate some level of risk.

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