I recently signed up for a medical study.
Next week, I get to go to the sleep center and sleep there. They pay me money for the night I stay.
Then they are going to give me pills to take and tell them what happens.
So, I get to put their product into my body and then tell them how it makes me feel, and I have to go sleep in their bed and I get paid...
Hurray for selling my body to a research company.