Starting Sunday, your Amazon purchases will cost more

Amazon addicts, you might want to fill up that online cart before Sunday.

For the first time, the online retailer will be collecting sales tax from Iowa customers.

Earlier this month, the company announced it would be required to collect Iowa's 6 percent sales tax at the beginning of 2017. But it's unclear what prompted the change. Amazon officials did not respond to a request for comment.

"They’ve agreed to do this," said Victoria Daniels, spokeswoman for the Iowa Department of Revenue. "They approached us."

Amazon charges sales tax in 30 other states. And several state governments have moved in recent years to capture a piece of the online giant's revenues, which topped $100 billion in 2015.

Iowa law requires companies with a "nexus" in Iowa to collect sales tax for online purchases. That means stores with a brick-and-mortar presence such as Target and Barnes & Noble must collect sales tax on their online orders. For retailers such as Amazon without a physical presence here, the burden is on the consumer to send the state an equivalent use tax, though few actually pay.

Although the state did not mandate the change, Daniels said it is a win for Iowans.

"It’s a huge concern," she said. "Not so much from a revenue perspective, but it’s a matter of fairness."

That's because Amazon competes with Iowa retailers, who support public infrastructure by paying property taxes and charge their customers the mandated sales tax rate.

"It’s a competitive disadvantage for them," she said. "Iowa customers are buying (Amazon) products, using those products here and benefiting from those products, yet that company does not have the same tax burden."

Most grocery items are exempt from sales tax, though candy, certain beverages, pet food and other exceptions exist under Iowa law.

The Department of Revenue estimates Iowa loses between $18 million and $24 million in sales tax collections to online retailers with no local presence. In fiscal year 2016, the state collected nearly $2.3 billion in total retail sales taxes, according to the Department of Revenue.