Anyone can file a SIMPLE return for free which is explained below. If you are under 25 and not filing a simple return then everything else costs you only $15.
There might be donations in box 46 of your T4 or Employee-paid premiums (medical) in box 85 of your T4 which would require an upgrade to allow you to claim additional credits not included in the free version. Please see the list below enumerating what is or is not included in the free version.