Do i need to report approximately $100 of bit coin I won in a contest? I cashed it out immediately and ended up with around $97. What will happen if I don't?

Without a 1099-MISC, the IRS will not have a record of this income. It is your responsibility to report it on your tax return. 

(If you only won $100 in the contest (and took it as a cash payout), you probably won't get a 1099-MISC).

You can follow these steps to enter these winnings: 

Sign In to TurboTax Online

• Click "Take Me to my Return"
• Click "Federal" from the left side of your screen
• Scroll down to "Less Common Income" and click "Show More"
• Click "Start" to the right of Form 1099-A, 1099-C
• Scroll down to "Other Reportable Income" and click "Start"
• On the Any Other Taxable Income? screen, click Yes.
• On the Other Taxable Income screen, add a description and the dollar amount.
• Continue with the onscreen interview until complete.