When Amy Sinnwell, an elementary school teacher in Iowa, paid her property taxes, she wasn't expecting to get any money back. But she ended up getting $500 from the Iowa State County Treasurers Association's "Get Back" contest, which gave an award to one randomly chosen taxpayer who filed online.

Ironically, Sinnwell won the contest without even knowing that she had entered. Like many people, she tacks a certain amount onto her mortgage payment each month, and leaves the actual tax payment to her mortgage company. Luckily for her, the mortgage company decided to file her taxes online, making her eligible for the contest.

Lana Taylor, Poweshiek County treasurer and president of the Treasurers Association, notes that the $500 did not come from taxpayers' money. The contest was sponsored by Bank of America, which is also putting up $500 for a drawing in April for those who file their taxes twice a year. The Treasurers Association plans to do the contest next year as well, if they can continue to fund it with sponsorships.

The treasurers hoped the contest would increase publicity for online filing, which saves their staffs a tremendous amount of time. The marketing campaign seems to have worked: 150,000 residents filed their property taxes online in September.

There is a slight downside for the taxpayers, however. A surcharge is added on to the online filing: $2 for electronic bank account transfers and 2 percent for credit card charges. But Taylor urges residents to think of cost in relative terms. "You can hardly pay for the cost of stamp and envelope and go to the post office for less than $2," she says.