It actually goes the other way, the litmus test is something like this: - is the student doing something that tangibly contributes to the business? - is the s

It actually goes the other way, the litmus test is something like this: - is the student doing something that tangibly contributes to the business? - is the student doing something that you would normally pay an employee to do? If the answer to either of those questions is yes, you should pay the student/intern. Of course, IANAL, and this only applies to the ISA, but that is how acquaintances who are self-employed handle their interns. The only time you can have an unpaid intern is when their work is substantially education, and does not contribute to the bottom line.