Free workers could sell their labor to employers on their own terms.

These people are selling their labor at very low rates.

Instead of trying to sell his labor on the open market, or jumping at opportunities, he'd be tied down.

People are not willing to sell their labor and work for us.

The working class are those earning their wages by selling their labor.

That is, we do not have to rely entirely upon selling our labor.

Equivalently, it is the lowest wage at which workers may sell their labor.

The suppliers are individuals, who try to sell their labor for the highest price.

Do you have the right to sell your labor at a fair price?

Up to now the majority of the population participated only by selling their labor.