There is no objective standard for "exploitation". We design arbitrary ones, and even those have to be enforced (minimum wages, for example). And you are right

There is no objective standard for "exploitation". We design arbitrary ones, and even those have to be enforced (minimum wages, for example). And you are right, higher prices lead to less consumption. Basically any employee contract is a cooperation between two parties leading to a shared benefit of that cooperation. How that benefit is partitioned between the two parties is a matter of negotiation and negotiation power.