proletariat
The proletariat is anyone who needs to sell their labor to live.
The proletariat is the class of modern wage laborers who having no means of production of their own are reduced to selling their labor power in order to live.
- Fredrich Engels, the communist manifesto
That is all that is required to be part of this class. This means that regardless of a person's income or living situation any person who must sell their labor in order to survive all have similar class interests and can collectively use their power to put pressure on the capital owning class.