We study individual demand for COVID-19 antibody tests in an incentivized study on a representative sample of the US population. Almost 2,000 participants trade off obtaining an at-home test kit against money. At prices close to zero, 80 percent of individuals want the test. However, this broad support of testing falls sharply with price. Demand decreases by 19 percentage points per $10 price increase. Demand for testing increases with factors related to its potential value, such as age, increased length and strength of protective immunity from antibodies, and greater uncertainty about having had the virus. Willingness to pay for antibody tests also depends on income, ethnicity and political views. Trump supporters demonstrate significantly lower willingness to pay for testing. Black respondents, even if critical of Trump's approach to the crisis, pay less for testing than white and Hispanic respondents. If policy makers want a broad take-up of testing, the results suggest that tests should be free.