You may not have to pay to get this filled out and to the IRS. Source: Internal Revenue Service.

"There ain't no such thing as a free lunch."
Robert Heinlein

Doing your taxes can be a pain. It can also be expensive. However, there are ways that lots of Americans can do their taxes -- both federal and state -- completely free of charge. Here's a closer look at the three best ways to do your taxes for free. 

1. Old-school forms, but easier 
When it comes to your federal return, the Internal Revenue Service offers its "Free File Fillable Forms" online service. Using this service, you can fill out your IRS tax forms online, and the system will automatically do the math on the forms for you. If you have a very basic tax situation, or a solid understanding of how to file if your situation is more complex, the old-school forms, with modern online improvements, may be the best way to go. And they're free!

You can also download state income tax forms from your state's website. The majority of states also offer digital forms you can fill out either online, or on your computer, though few offer forms that will do the math for you like the federal program. 

2. Free tax-preparation software 
Before you fill out the forms, however, you may qualify for free tax-filing software. There are more than a dozen reputable companies that offer free federal tax-filing software -- typically done online -- for people who qualify. The qualifications vary by provider, and may include free state income-tax prep, as well. Before you just click on the one that's most familiar to you, take a few minutes and compare. 

Depending on a few factors including which state you live in, you might be able to get free tax prep on your state income-tax filing, too. 

Also, read the fine print, and make sure you understand what you're choosing when it comes time to file. Most of the companies that offer the free tax prep will offer you a number of options when it's time to actually file. This will include a number of things that you may have to pay for, such as an accelerated return (often a short-term loan that's paid off when the IRS issues your return), IRS audit protection, or other things that you may not need, but may choose to pay for. 

3. Free in-person tax preparation 
That's right -- free tax preparation, and by an actual human being! The IRS's Volunteer Income Tax Assistance -- or VITA -- program offers free tax preparation for people who meet a number of qualifications, including income, age, disability, and other factors. In addition to free tax preparation for qualifying filers, the IRS' Tax Counseling for the Elderly program is a great resource, especially for those 60 and over, helping answer questions about retirement, pensions, and other issues that seniors face.