Wage slavery is similar owning and renting a person.
I have heard some talks about this recently. Im not all that familiar with the subject though.
 It is usually used to refer to a situation where a person's livelihood depends on wages or a salary
Is it hard for someone to leave that situation?
I would say yes because in sweatshops), and as a lack of workers' self-management, fulfilling job choices, and leisure in an economy. Its hard to do anything else.
Oh I see now. Yea that does sound difficult. Are people doing anything about this?
In some ways yes and some no. It has been criticezed because of the exploitation of labour and social stratification, with the former seen primarily as unequal bargaining power between labor and capital