@ABM1707 There is no minimum dollar amount of income that triggers a filing requirement for a nonresident alien, including a foreign student or a foreign scholar.
Referral fees are considered taxable income in the US regardless of the amount and in your case any amount $600 or more requires a 1099.
An F1 student can have income.
This is not considered earned income. It is unearned, just like dividends and interest would be. While there may be limitations, i don't see $600 as unearned income hurting you but, you will need to file.
Sorry, if this is not what you wanted to hear.