The first coupon ever created was, unsurprisingly, invented by the Coca-Cola company in 1887. The coupons offered a free sample of the year-old drink, which was initially sold for 5 cents. In 1895--just 8 years later--Asa Candler proclaimed that Coca-Cola was sold and consumed in every territory of the United States.
By the early 1900s, coupons became so ubiquitous that this 1906 New York Daily Tribune article ironically proclaimed "A Great Future is Predicted for the Rebate Coupon." Then--as now, with Groupon--there were skeptics who weren't quite sure that all the savings were worth it:
"One may imagine the non-transferable feature of rebates amended so that the little checks and coupons may be included in legacies. The last will and testament of John Jones will bequeath to his beloved heirs 5,000 pink stamps, 2,263 brown coupons, 967 olive checks and a lesser assortment to complete the kaleidoscope."
The tongue-in-cheek article goes on to playfully suggest a political use for coupons: "It may be assumed that political parties and candidates already issue varieties of trading stamps that are mostly worthless after election. Pledges and platforms glow with the fading iridescence of true rebates. A few coupons guaranteeing a round of government seed, a front seat at an inaugural, the privilege of finding fault and voting on the other side next time, might heighten enthusiasm in a campaign."
A thought for the 2012 election, perhaps?