PHOENIX - Arizonans who bought a new car or truck last year may be helping fund the campaign to kill Proposition 204.

The Arizona Automobile Dealers Association asked its members to pony up $2 for every vehicle each of them moved in 2011. The result was a donation of nearly $339,000 to the anti-Proposition 204 effort, making it the second-largest single source of cash for the campaign.

Bobbi Sparrow, president of the organization, said members are concerned about where the $1 billion a year that would be raised by the proposition will be going. She pointed out that while most of the funds are earmarked for public education, the initiative also promises shares for everything from welfare programs to road construction.

But Sparrow said there's also an element of self-preservation for the dealers, who sell pretty much the most expensive taxable item in Arizona.

She said there already is a problem with Arizonans buying vehicles elsewhere because of the state's high vehicle license tax. That annual levy is based on the value of the car or truck, meaning it is most expensive on new vehicles.

"Now our sales tax is going to be the highest besides Tennessee," Sparrow said. She predicted the savings from a 1-cent difference in sales taxes - about $250 on a $25,000 vehicle - coupled with the lower vehicle license tax elsewhere will just prove too much for some customers.

But initiative organizer Ann-Eve Pedersen said the dealers' claims ring hollow.

"They had a great sales year last year," she said, and that was with the state sales tax already at 6.6 percent, including the temporary 1-cent surcharge approved by voters in 2010.

Pedersen pointed out the tax imposed by Proposition 204 would not take effect until June 1, the day after the temporary levy expires.

"So nothing's changing," she said. "And so I don't see why if they had a great sales year last year with the 1 cent in place, and all we're doing is maintaining that same 1 cent, the car dealers would be taking issue with this."

Sparrow is not releasing a list of which dealers contributed and how much each gave.

She said the association's board asked for $2 per vehicle "just to start getting dealers thinking" about what would be a fair contribution.

"We had some dealers that didn't give anything; we had some dealers that gave more than the $2," Sparrow said. "We had some that just gave us a flat amount."

Pedersen, for her part, said she and other supporters will do what they can to figure out who gave money. And she suggested that there might be a benefit for those who did not donate to publicize that fact.

"I have to buy a new car because my car conked out from all this driving all around the state" to promote the ballot initiative, Pedersen said. That's leaving her in a rental vehicle for the time being. "At the end of the campaign, I will be buying a new car," she continued. "And I'd like to know who did not contribute."

Sparrow said she's not against funding of education, pointing to her previous employment as a lobbyist for the Arizona School Boards Association. But she said there are concerns that not all of the money is going for education.

Pedersen, however, said the dealers' opposition is strictly political. She said the group is seeking to curry favor with Gov. Jan Brewer and Republican lawmakers who are opposed to the initiative.