Since you received a cash prize, the amount received is also the
Fair Market Value (FMV). TurboTax asks if there is any
adjustment
to FMV.
If you entered prize winnings from a 1099-MISC in TurboTax, once
entered you will see a screen titled "Fair Market Value of Prizes and
Awards". There will be a box next to Adjustment to Value of Prizes and
Awards. Having received cash, you will leave this box blank.
(If you had received an item, there may be a difference between the FMV of the
item and what was reported to you.)
See screen shot below.
To get back to the "Fair Market Value of Prizes and
Awards" screen:
Once in return: Federal Taxes -> Wages & Income
-> Other Common Income -> Revisit Form 1099-MISC -> Click Done
on "1099-MISC Summary" screen
