system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does money work in prison? Are there things you can buy with cash? Do you have access to your bank account?
gpt
There is no physical legal cash in prison, friends and family can put money in an inmate's commissary account, which they can use to buy things.

Other things become cash-like within prison, cup-of-noodles, packets of instant-coffee and such take the place of cash within prison, and are traded among inmates for other goods/services.