Where do I enter commission income? "uncommon income" or "Additional and other income"?

To enter your commission income:

• Go to Federal  > Wages & Income
• Scroll down to the Other Common Income section
• Click Start next to Form 1099-MISC
• Answer Yes to Did you get a 1099-MISC?

At the screen "Does one of these uncommon situations apply", select "None of these apply". If you answer all 3 of the next questions no; TurboTax treats it as other income rather than self employment.

•  No, didn't involve work like main job
• Only got the income in 2017
• It didn't involve an intent to earn money

If you don't have a 1099, you will still need to enter any commissions you earn.  As to where you enter it depends on why you received the commission.  If you are a salesperson and this is your career, then you would enter it using TurboTax Premium in the Self-Employment section.  You will walk through the questions and answer the entering your income and expenses based on your records.  If you are self-employed, you can deduct things like your mileage and home office expenses if you qualify.  As you walk through the program, as long as you read and accurately answer the questions, TurboTax will help you get the most deductions you can.

If this was a one time thing you did and received a commission for something like a referral, then you would enter it as Other Income by taking the following steps:

• Income 
• Show more next to Less Common Income
• Start next to Miscellaneous Income
• Start next to Other Income not already reported on a form W-2 or 1099. 
• Walk through until you get to the question asking "Enter Source of Other Earned Income and select Other
• Enter the description and amount.