The best online tax filing method for Montana residents is the one that’s easiest and fits budget and time constraints. Gone is the need to labor over thick IRS and state instruction booklets. This method eliminates guess work in terms of tax code changes, changes in Health Care credits or penalties, even math errors. Calculations are automatic as you enter your numbers on the lines of the form. As state and federal tax agencies go “green,” they are actually encouraging taxpayers to file electronically because it eliminates paper waste and printing costs, as well as being more efficient.