SAN FRANCISCO — Tax-free shopping is under threat for many online shoppers as states facing widening budget gaps increasingly pressure Amazon.com Inc. and other Internet retailers to start collecting sales taxes from their residents.

DES MOINES, Iowa - A coalition of 18 states representing about 20 percent of the nation's population has forged an agreement to begin collecting sales taxes on Internet purchases.

WASHINGTON — Booming sales on Cyber Monday might have meant savings for consumers, but they could also have meant lost revenue for the state of Arizona, a new report said.

The Arizona Retailers Association is gearing up to mount a public-relations campaign to garner support for requiring online retailers to collect state sales tax.

State lawmakers will make a bid Wednesday to close a loophole which allows online retailers to avoid collecting hundreds of millions of dollars of sales taxes.

When it comes to online businesses, big and small, Arizona is a haven.

When it comes to online businesses, big and small, Arizona is a haven.

The explosion of Internet sales is fueling a new debate over whether Arizona should try to force out-of-state firms to collect the state sales tax.

The explosion of Internet sales is fueling a new debate over whether Arizona should try to force out-of-state firms to collect the state sales tax.

Someone is going to have to address the issue of whether Arizonans -- and others -- should be charged sales taxes on purchases they make online, Gov. Jan Brewer said Thursday.

Someone is going to have to address the issue of whether Arizonans -- and others -- should be charged sales taxes on purchases they make online, Gov. Jan Brewer said Thursday.

California lawmakers thought they were targeting Amazon.com, the out-of-state giant, when they voted last week to force Internet retailers to collect sales tax.

California lawmakers thought they were targeting Amazon.com, the out-of-state giant, when they voted last week to force Internet retailers to collect sales tax.

California lawmakers thought they were targeting Amazon.com, the out-of-state giant, when they voted last week to force Internet retailers to collect sales tax.

Arizona residents who opted to pay taxes for online purchases have given the state a slight windfall.

Arizona residents who opted to pay taxes for online purchases have given the state a slight windfall.

Backers of extending the state's temporary 1-cent sales tax submitted more than 290,000 signatures Monday to put the issue on the November ballot.

Backers of extending the state's temporary 1-cent sales tax submitted more than 290,000 signatures Monday to put the issue on the November ballot.

Two new reports on the cost of changing how construction activity is taxed could torpedo the sales tax simplification plan being pushed by Gov. Jan Brewer.

A bill working its way through the Arizona Legislature is hoping to make retail fairer by forcing Amazon.com and other online retailers that have a presence in Arizona to charge a state sales tax.

Tempe voters will decide May 18 whether to approve a .2 percent sales tax increase for the next four years.

PHOENIX -- Arizona is moving toward making online merchants collect sales tax on residents' purchases, a departure from the state's previous hands-off stance.