Answer:
Indentured servants.
Step-by-step explanation:
Indentured servants are immigrants that come with the prospect of working for a certain amount of time free of cost for the employer. And in return, the servant will be free to work for himself by the end of his 'servitude'.
Indentured servants are different from slaves. They are more important and treated better, not as properties but rather as passengers. Moreover, they can work without a salary for a certain amount of time ranging from 4-7 years, and then be free after the 7 years are done. They can marry, study and even work wherever they want, and even start their own business after their years of servitude are over. Simply put, indentured servants are 'free' once they finish their years of 'internment' or promised servitude.