TurboTax Premier Online covers:

• income and expenses from stocks, bonds, and cryptocurrency
• interest income (with or without a slip)
• rental property income and expenses
• capital gains and losses
• foreign income

If you have any of these on your return, then you need to use Premier.

Unfortunately, once you have upgraded or added features to your TurboTax return, there is no way to downgrade or remove the extra features. You would need to create a new return to go back to the original product. 

To start a new return, select “Start a New Return” from under “My Returns” in the top left corner. Once you have started your new return, you can select “View All Returns” from under “My Accounts & Returns”. Then delete the unwanted return by clicking the small Trash Can next to it or “Delete” under the return’s name.