I am a dual citizen. What is the best way to file?

With regard to affordability, you can shop the various Canadian versions of TurboTax here:

https://turbotax.intuit.ca/tax/software

And the U.S. versions here:

https://turbotax.intuit.com/

If you are a US citizen, you are required to file a US tax return and report and pay tax on all your world-wide income, no matter where you live, that's one of the prices you pay for the benefit of US citizenship.

If you pay foreign taxes on the same income, you can claim a credit or deduction on your US tax return for those foreign taxes.  

If you lived and worked outside of the US for at least 330 days of the year, you can exclude your foreign earned income from US taxation.  Earned income is income earned from providing a service.  However, you can't exclude unearned income and must still pay US tax on unearned income (unearned income is anything that was not paid to you as compensation for providing goods and services and includes capital gains, interest, dividends, prizes, and some other things).

Turbotax does include both the foreign tax deduction/credit and the foreign earned income exclusion.