Installment fi nancing can be discovered in many forms in everyday fi nances. One popular
example is a “no-interest program” offered by retail stores on the sale of major appliances, audio
and video equipment, furniture, and other consumer items. Many variations are possible, but in
most cases, if the purchase is not paid for in full by the time the promotion is over, usually
6 months to 1 year later, finance charges are assessed from the original date of purchase. Further,
the program’s fi ne print may stipulate that the purchaser use a credit card issued by the retail
company, which often has a higher interest rate than that of a regular credit card, for example,
24% per year compared to 15% per year. In all these types of programs, the one common theme
is more interest paid over time by the consumer. Usually, the correct definition of i as interest on
the unpaid balance does not apply directly; i has often been manipulated to the financial disadvantage
of the purchaser. This was demonstrated by Example 4.4 using the Credit Card Case in
Chapter 4.