If you haven't finished your taxes yet, there's still time before the April 18 deadline. And if your return isn't too complicated, you can take advantage of some low-cost or free tax preparation options online. 

All three of the major tax-prepration brands—H&R Block, TaxAct, and TurboTax—offer free versions to help you complete your taxes and e-file them. But if you are self-employed or have income from capital gains, for example, you'll probably have to pay anywhere from $27 to $115 for federal tax preparation products.

The IRS also offers taxpayers with adjusted gross incomes below $64,000 free federal tax preparation services.

Here's a look at some of the free or low-cost options. 

H&R Block

Of the three services reviewed here, H&R Block More Zero Free Edition is the most robust. In addition to free, guided preparation and e-filing of federal forms 1040A, 1040EZ and Form 1040 (the "long form"), this product is the only free offering among the major tax preparation brands that includes Schedule A, which covers itemized deductions. With Zero Free, you can also prepare and file one state return at not cost (additional state returns cost $39.99).

If you want to use this service, you need to act quickly.  At midnight on March 31, H&R Block will replace it with H&R Block Free which does not include Schedule A and does not provide experts to answer questions you may have. H&R Block Free only supports Form 1040EZ and Form 1040A. 

If you need to prepare the 1040 "long form" with Schedule A, you'll have to upgrade to H&R Block Deluxe, at $54.99 for federal and $39.99 for state.

To complete your state tax forms and e-file them, you'll have to pay $29.99. 

If you run into technical problems while using the service, there is free support. If you need tax advice, however, you'll need to upgrade to H&R Block Deluxe, which costs $34.99 for federal returns. 

A useful feature of the online service is that it will automatically import your W-2 data from your employer as well as form 1095-A from your health insurance marketplace, and forms 1099-INT, 1099-R and 1099-DIV income forms.

You have the option to photograph your W-2 from your smartphone or tablet and upload it as well. 

TaxAct

If your taxes are more complicated, TaxAct Online 2016 Free Edition provides free, guided preparation of IRS Forms 1040A and 1040EZ, as well as a number of common tax documents such as Form 1095-A and the Health Insurance Marketplace Statement. It also provides free tax preparation and filing for one state return. Additional states cost $33 each.

A great feature is that TaxAct provides certified public accountants and "enrolled agents," to answer your questions. Enrolled agents are not as highly trained as CPAs, but they are federally authorized to prepare tax returns.  You can reach them by phone (319-373-3600) or by chat and email.

Another benefit: TaxAct lets you access up to three years of prior-year returns completed online through TaxAct at no charge. If you need to transfer data from your prior-year TaxAct return, however, you'll pay $10.

If you are so inclined, you can even use the free service on your smartphone to prepare and e-file state and federal returns. You'll need to download the TaxAct Express app.

The app covers even more services including the Form 1099-INT and the 1099-DIV. (TaxAct warns that if you switch over to a browser or tablet app to finish and e-file your form, you're subject to TaxAct's online pricing.)

TurboTax

TurboTax's Federal Free Edition also offers free, guided tax preparation and e-filing service for federal returns, but you'll pay extra for your state return (currently $29.99 per state). Only taxpayers who use IRS Forms 1040EZ or 1040A can use this version, which is available for laptops, desktops, and mobile devices.

TurboTax will import your W-2 information from participating employers, but if your employer isn't included, the program will let you photograph your W-2 on your smartphone or tablet using the TurboTax app. The app will automatically populate your tax form. You can then continue to prepare the form, either on your phone or your computer

With TurboTax's free edition, you can't communicate with an expert in real time if you need tax advice. (You can, however, use the online "AnswerXchange" that includes questions and answers from TurboTax experts and other contributors.)

Other services, including transferring your data from a prior return prepared using TurboTax, require that you upgrade. 

IRS Free File

To access IRS Free File, your 2016 adjusted gross income must be below $64,000. To use the service for a federal return, visit the IRS Free File portal, and then select from a dozen private providers.  

Keep in mind, though, that if you need to file a state return, you may have to go through your state portal to find out which software products will support your state taxes.

If you start with IRS Free File, click on the blue "Start Free File Now" button. You'll see a listing of 12 do-it-yourself tax preparation brands. Since all have different eligibility rules, you'll have to sift through them to see which works best for you.

There is also a Lookup Tool option at the top of the page that you can use to winnow down the best programs for your needs. 

If you start with your state portal, you should be able to also complete the federal return for free. In New York, for instance, eligible taxpayers must start at the state’s free-filing web page to be linked to the appropriate online tax preparer. That service then handles both state and federal returns for no cost.

Blank IRS Forms

If you don't need help filling out your forms, the IRS also offers free blank forms. These "fillable" electronic versions of Forms 1040, 1040A, and 1040EZ are available to all taxpayers, regardless of income. When you fill out the form, the electronic version automatically completes all the calculations for you.