You will enter the amount under "Other Reportable Income not reported on a Form W-2 or 1099".
Here are the steps in TurboTax Deluxe online edition :
1. After sign into your account, select orange button Take me to my return
2. Top right corner / in the search box- type in " other reportable income" and Enter
3. On screen, "Other Wages Received", answer Yes / continue to follow prompts, skip the screens which do not apply to you.
4. On screen, "Any Other Earned Income", answer Yes
5. On screen, "Enter Source of Other Earned Income". answer Other
-If your employer did not take out your FICA taxes, you might need to select Employee compensation that was not reported on a W-2. ( Click to see if it applies to you)
6. On screen, "Any Other Earned Income", enter description and amount.