Loyalty programs are also available on some transit systems, where frequent use of the system results in greater discounts on fare payment.
But Texaco agreed to $52 million in discounts over the next two years to offset the higher interest rates.
But it soon found that many vendors would not accept the currency for large payments, which translated into a $16,000 hit in discounts.
Those include $1 million in travel accident coverage and discounts when renting a car.
The strong demand has also resulted in smaller discounts and lower rebates, enhancing dealers' profits.
The study found that investors eligible for breakpoints were entitled, on average, to $364 in discounts they did not receive.
The city was entitled to $1 million in discounts for paying its bills promptly to the truck manufacturer.
With crowded planes and higher fares it would be easy to conclude that passengers aren't interested in discounts.
Get everything that Medicare covers and more, including $500 a year in prescriptions and discounts on dental care.
Ten thousand miles, for example, would convert to $200 in discounts.