HARRISBURG - Thousands of Pennsylvanians who purchased cartons of cigarettes over the Internet or by mail order have been sent letters by the state Revenue Department informing them that they owe taxes.

The first batch of letters went out about two weeks ago to 4,300 people who are believed to have purchased at least 100 cartons and collectively owe $10.4 million in taxes. More than 700 of them have enrolled in a payment plan, Revenue spokeswoman Stephanie Weyant said yesterday.

The largest purchase was 975 cartons, resulting in nearly $15,000 in unpaid cigarette and sales taxes.

"Some Web sites falsely advertise that cigarettes are tax-free, and that's simply not true, and unfortunate," Weyant said. "Some have now started putting a very-fine-print disclaimer on their Web site."

Esther Brown, a 71-year-old widow from Scranton, said she ended up with a $2,100 bill after buying 125 cartons for her daughter and some of her daughter's friends. Her payment plan requires $300 up front and $147 a month, but her only income is a $1,000 monthly Social Security check.

"I was going to see if I can put it on a credit card or something," Brown said yesterday. "I can't do this. How am I going to catch up on my gas and rent then?"

A federal law requires companies that ship cigarettes across state lines to release information about the sales to taxing authorities in the state where the purchaser lives.

Pennsylvania has obtained records pertaining to about 27,000 buyers going back to the start of 2005. The state will attempt to contact all of them, Weyant said.

Pennsylvania assesses a $1.35-a-pack cigarette tax and a 6 percent sales tax. It is sending tax forms to the online and mail-order purchasers, and waiving penalties for those who pay or enroll in payment plans.

Weyant said at least 13 other states have also begun mining the sales data to collect their own taxes.