IRS Free File is exactly what the name says

The IRS says 70% of U.S. taxpayers qualify for its Free File service, which helps you complete and file your taxes at no cost. (Or as the tax agency's website puts it, "for less than a penny.")

According to the IRS, Free File has saved Americans more than $1.6 billion in filing fees since its launch in 2003.

Here's how it works: If your income is $66,000 or less, you file using a free version of popular, commercial tax software such as TurboTax, H&R Block or Jackson Hewitt.

What if you earn more than $66,000? The free software isn't available to you, but if you're willing to try tackling an old-fashioned tax return on your own, you can use "Free File Fillable Forms." (Just try to say that five times fast.)

Note that while Free File is free, there can be related charges, such as a credit card fee if you use plastic to pay any taxes you owe, or a charge to file your state taxes with the same commercial tax-prep service.

Using Free File software

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You use a free version of popular, commercial tax software.

If your income qualifies you for Free File software, go to IRS.gov/freefile. Choose the option best for you, and you'll be directed to click through to the company's website. (You might save a step and go directly to the site of a provider, like H&R Block.)

You'll need to have a copy of your last tax return handy, along with your W-2 and any other documentation of your income and deductions.

Never used tax software before? It's incredibly easy and goes step-by-step through your return by asking a series of questions to fill in all of the blanks. At the end of the process, you file your return eletronically.

The IRS says you save time and will get your refund faster, particularly if you opt to have the money direct-deposited into your bank account.

Using 'Free File Fillable Forms'

Person filling in a tax return on a computer screen
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You fill in all of the lines on a tax return manually, on your computer screen.

The Free File version available to higher earners requires you to keep things somewhat lower-tech and fill in a tax return manually, on your computer screen. You'll also need to know which additional forms and schedules to file with your 1040.

You still can file your return electronically and have any refund direct-deposited. If you owe money, methods to pay include by check or through an electronic funds withdrawal.

While 50 million people have already used the two Free File options, another 50 million are eligible but haven't yet benefited. "It's not advertised, so nobody knows about it," explained Tim Hugo, the executive director of the alliance of participating tax software providers, in an interview with CNBC.

Taxes aren't going to get any simpler, despite the promises that one day we'd all be filing on postcards. You're probably going to need help with your return — so don't pay for it if you don't have to.