Final answer:
Prisoners earn money for commissary and phone calls through payments for labor they perform while incarcerated. This has historical precedent where POWs and other prisoners were allowed to work voluntarily for small sums, which they could use for personal expenses within the prison system.
Step-by-step explanation:
Prisoners earn money for commissary and phone calls primarily through payments for labor. This practice is not new and has historical roots in how POWs and convicts were treated. Although the Geneva Conventions prevent compulsory labor, prisoners often perform voluntary tasks that are in demand such as farming and forestry work for which they receive a small sum. Additionally, funds can be organized by outside entities to support the needs of prisoners.
The amount earned by prisoners is usually very modest and the conditions under which they work can vary greatly. In some cases, payment for labor can hardly cover their basic needs and at times is left up to the discretion of prison management. Moreover, the decision for a prisoner to work might not be entirely voluntary as they may feel obligated to take advantage of the limited benefits offered.
In historical contexts, such as during World War II, prisoners were provided with the necessities such as food and clothing, but also had opportunities to earn money through work. This practice continues in various forms in contemporary prisons around the world. The income earned can then be used to purchase items from the commissary or make phone calls.