system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do coupons always say "cash value 1/20 of one cent" or something similar?
gpt
During the early 1900s, stores had trading stamps, where for every dime you spent at the store, you got a stamp, and when you saved enough stamps, you can mail in those stamps for free merchandise (Kind of like an analog version of Areoplan Cards). These stamps were HUGE business back in the day.

But merchants had to pay the stamp makers for the stamps and that payment increased prices of goods, custumers who didn't collect stamps thought that the price increase was unfair so Congress passed a law saying that the stamps had to have cash value so that customers can redeem them directly with the merchant for money (thereby offsetting the increase in good prices.. And the 1/20 of one cent was a considered a fair price back in the early 1900s. In certain states, coupons are still considered trading stamps, so by law, they have to include the disclamer.