The price you pay for the TurboTax App/TurboTax Online is based on what you enter on your tax return. If you choose add-ons like Assist & Review or the Premium Pack (Audit Defence) then the price of those services will also be added onto your return.
Also, if you prepare your returns together with a spouse/partner, then both people will be using the same version of TurboTax, and so you’ll be charged the same amount for both returns.
Additionally, most TurboTax discounts & promotions end on April 30, so in the past you might have taken advantage of a promotion that is no longer available.
Please see this TurboTax Canada FAQ for more information on who can use Free: Who can file for free using TurboTax?