(MONEY Magazine) – The Tax Crusader Gordon Walter Rayville, La.

In July 2003, Louisiana stores were supposed to stop charging 4% sales tax on most food items. But when appliance repairman Gordon Walters, now 57, bought his usual Diet Coke one day, he still was charged the extra nickel. He called the state department of revenue and was asked to mail in receipts from any store that charged the tax. So he bought more sodas--500 more, in fact, from stores across the state. Most continued to charge the 4%.

State officials contacted the stores but, as far as Walters could tell, didn't crack down. After his appearance on a radio show and in an Associated Press story, however, the state began a campaign to educate store owners. Hurricane Katrina slowed efforts, so Walters recently collected another stack of receipts. Persistence, he says, is the only way to battle a bureaucracy. Walters has spent two years and more than $2,000, he estimates, on the fight. (And he drank every last drop.) "At least they finally said, 'We have a problem,'" he says. "You have to stand up and stick with it."