Wells Fargo customers have paid down $50 million in mortgage balances since the mega bank unleashed its Home Rebate Card in 2007, just one year before the housing market crash. 

Unlike a lot of other mortgage products that failed, the credit card managed to stay afloat and proved to be quite beneficial to homeowners.

The card is unique because every purchase a customer makes with the card counts toward rebates credited to the principal on their Wells Fargo mortgage.

This may seem insignificant, but over a 30-year period it can make a substantial dent in what they owe, allowing borrowers to piggy back off their normal monthly expenses.

For example, Wells Fargo claims a cardholder with a $150,000 mortgage who spends $1,500 a month on the Home Rebate Card could shorten their payment schedule by more than a year.

"The card is just one example of how we help customers make smart use of their money and achieve their financial goals," said Beverly Anderson, head of Wells Fargo’s [stock WFC] [/stock] Consumer Financial Services group.

She explained, "The Home Rebate Card provides a way for customers to manage day-to-day spending while automatically paying down what is likely their largest debt – their mortgage."

Ultimately, the company said the card can help customers potentially reduce their long-term mortgage interest by thousands of dollars and lower the number of remaining payments.