In mining/mill towns (any town owned by a company) there was a common practice of paying workers in "scrip," valueless pieces of paper that could only be redeemed at the company store
, which often charged outrageous prices, which exacerbate
d the cycle of wage slavery
Hence the song:
You load sixteen tons and what do you get?
Another day older and deeper in debt.
Saint Peter, don't you call me 'cause I can't go,
I owe my soul to the company store.