If you make less than $34,500 a year, or make in this neighborhood and have children, by all means use the online "TurboTax Freedom Edition" (not TurboTax Free Edition), because it has many powerful features for free.
If you are self-employed and make less than $34,500 a year, absolutely use TurboTax Freedom Edition. You can't afford $75-120 for the Home & Business Version.
In general, if you make more than $34,500 a year and want to use a cheaper version than Intuit recommends for your tax lifestyle, stay away from the online versions; use the CD/download versions. You can print out the forms you need and file them on paper, though this waives a guarantee and prevents e-filing.
If you make more than $34,500, but you don't have income from businesses, rentals, or complex investments and you don’t itemize deductions, you can use TurboTax Free Edition online (not Freedom Edition), but expect to be encouraged constantly to pay for additional services, including anything related to your state return(s).