What if my Crypto sold and cost basis was < $0.00? How do I record this number?

You still need to report it.  If it is just one transaction, you can enter it manually by following these steps. 

If you are using TurboTax on-line, 

1. go to the Income & Expense section, 
2. then scroll down the page to Investment Income, and 
3. click on the drop-down arrow to reveal all the options.  
4. Select Stocks, Cryptocurrency, Mutual Funds...

You may have already seen the page "Let's import your tax info."  At the bottom of that page is the "I'll type it myself" button.  Click on that button and enter your information.

In TurboTax desktop you will,

1. go to Wages & Income under Federal Taxes.  
2. At the page "How do you want to enter your income?" select "I'll choose what to work on."  
3. Scroll down to Investment Income, and 
4. select Stocks, Mutual Funds, Bonds.  
5. Answer the questions accordingly, but when you get to the page where you have the option to upload your documents, select the option to "Ill type it in myself."  Then enter your information. 

@tritondog