Scrip still has a pretty bad name in Appalachia. But it is important to sort out what it really was, and why it existed, and how it was actually used.
First, scrip was often issued as paper , or metal tokens, that were to be redeemed at the company store, but that store was a logical necessity. To operate a mine, an entire town had to be built to house and feed miners and mine workers, and a store had to be part of that. The company store was the financial and social center for the mine. Administrators had offices in the upper floors, and payroll accounts were kept there for miners. Tools, food and canned goods, even furniture could be bought. If there was a disaster, there could even be coffins and a cool place for bodies in the basement. Each miner would have hours and the number of cars loaded credited to his account there, and deductions for lights, coal, doctor's fee's , blasting powder, rent also logged in. They could draw on their account between scheduled paydays and get scrip, and they and their wives could use that for purchases at the store. There were constant battles between labor unions and independent merchants and coal companies over making scrip redeemable for cash, but most of the time it was not.
Most mines had a scrip system. But though mine companies came and went and financial documents for many, especially the small ones, have vanished, it seems that it was rare for miners to be paid exclusively with scrip. Miners usually could and would be paid in cash, as well- but that came on pay day, whereas the scrip was a kind of charge card, and the mine was ready to extend credit. Just like people with credit cards now, though, miners were quite aware of the dangers of it, how it was easy to fall into the trap of spending money they couldn't see.
It was a savings for the mine to be able to pay the workers in the retail value of goods it bought wholesale, of course. But the miners could and would spend money outside of the company store. Sears & Roebuck and Montgomery Ward were happy to send goods in by mail, or on the train, and local farmers would often come in and set up produce stands. And the company stores were sometimes near enough for miners to be able to shop at more than one. There was some competition, and so the typical prices at the company store do not seem to have been exorbitant, what you would expect of a monopoly- because it didn't quite have one. And though records exist of company store managers complaining about miners not buying enough in them, there seems to be no case of a mine company actually forcing its employees to buy at its store.
A newly-hired mine worker ( say arriving from Italy and brought in from the docks in New York) would also have to buy his own tools- pick, shovel, drill, headlamp, blasting powder- and those would be entered into his account: he'd have a debt immediately to work off, and through this in West Virginia there were examples of some miners being forced into debt peonage, before 1917. But that debt peonage was not because of scrip: the bottom line for miners, mine workers, was not scrip but really how much they were paid. A worker for the Low Moore Iron Company in Covington VA in 1902 got $28 a month. Deducted from that was $2 rent, about $1 doctor's fee, but an average scrip advance of only $7.12. In the early 1900's, in West Virginia a study found that Black mine workers ( who were often allowed only the poorer-paid jobs) spent about 72% of their wages at the store, native Whites 51% and foreign immigrants 33%. This is pretty astonishing. Until the boom years of WWI, these mine workers were paid poorly, and still somehow managed to keep a credit balance at the store and survive. Their families may have suffered, but they usually didn't owe their souls to the company store.
In the next boom, after WWII, the company stores dwindled greatly and the scrip system as well, as miners got better wages and automobiles and could drive elsewhere to shop.
Shifflett, C. A. (1991). Coal Towns: Life, Work, and Culture in Company Towns of Southern Appalachia, 1880–1960 (1st ed.). University of Tennessee Press.