Used to use TT when my financial picture wasn't as complex. Started using a CPA but I think I want to try my hand at doing this myself. I file 3 state and federal returns. One for my wife and I, one dependent son who has some investments and another son who is no longer a dependent but we still handle filing his taxes.
You'll definitely want to purchase the Desktop (CD/download) platform. Based on what you've said, you'll need TurboTax Premier (to cover the investments).
The Desktop program allows for up to 5 free federal e-files. You can actually prepare unlimited federal returns, but only e-file 5. With the Premier program, you'll get one free state tax preparation download. Each additional state tax prep program is currently priced at $39.99. You should also know that to e-file a state return using the Desktop program, you'll be charged a $19.99 fee. Of course, you can always mail a state return and avoid that additional cost.
I'll share the link below for ordering TurboTax Premier:
PS: You can also purchase the CD or downloads from multiple retailers, both in-store and online. And you'll likely find better pricing there.
I'm going to add this other info comparing the Online platform and the Desktop program, just FYI:
"What are the advantages of the TurboTax CD/Download software over the Online version?"