My 16-yo (dependent in my returns) won a science fair competition in May 2019 and received a check for $2000. Last week we received a 1099-MISC with that amount in Box 3. How should I handle filing taxes for this?
IRS Publication 929 covers tax rules for children and dependents. As of February 15, 2020, the guidelines refer to 2018 and do not appear to have been updated for 2019 taxes, but the numbers will be similar for 2019. Assuming your 16-year-old son is not blind and not married, because his unearned income (prize money) is over $1,050, he must file a return. See Table 1, Filing Requirements for Dependents, in Publication 929.
If your child and his income meet certain conditions, you may be able to report his income on your return. This is covered in the Parent's Election To Report Child's Interest and Dividends section of Publication 929. However, one of these conditions is that the child's income must be from interest and dividends only. Your child's income is not from interest or dividends, so it appears that you are not eligible to report his income on your return.
The draft version of Publication 929 for 2019 can be found on the IRS website and is dated February 11, 2020. In the draft, the threshold has risen to $1,100. The draft comes with the following disclaimer:
This is an early release draft of an IRS tax form, instructions, or publication, which the IRS is providing for your information. Do not file draft forms and do not rely on draft forms, instructions, and publications for filing.
At any rate, you should use Publication 929 as your guide. You can get a head start by following the 2018 version, but you should wait for the 2019 version to be released officially before filing your taxes.