My spouse: normal employment, T4. Me : self-employed T4A and numerous receipts Why do I pay as if both of us are self-employed?

If you prepare your returns together, then you are both using the same version of TurboTax, and so will both be charged the same price.

Another hitch: I do have two distinct businesses (sole proprietary), for which I used different T2125 forms.
The Turbotax online version for self-employed (I did upgrade) does not seem to allow me the distinction (I am at the earning section).
What would you suggest?  

Thank you,

You can create two different businesses. When you enter your T4A slip, that should make one automatically for the T-slip income, but you can create another once you get to the Self-Employment summary.