Rhode Island-based CVS Pharmacy has settled a lawsuit filed against it by Murrysville resident Mary Bach for improperly charging her state sales tax on two television digital converter boxes.

Mrs. Bach purchased the converter boxes at a CVS in Monroeville in January using two $40 vouchers issued by the federal government. The vouchers covered the entire cost of the boxes, but CVS charged her 7 percent sales tax, or $5.60.

In Pennsylvania, sales tax generally should be applied on the price of taxable items after any coupons are deducted.

CVS' computer system was reading the government vouchers as legal tender rather than a coupon, spokesman Mike DeAngelis said yesterday. "As soon as we were made aware of the problem, we corrected it," he said. Most other states require the company to collect sales tax on the full price of the item, he said.

Any Pennsylvania customers who believe that they may have been improperly charged sales tax should bring their receipt to the store for a refund, Mr. DeAngelis said.

CVS last week paid Mrs. Bach $100 in damages, plus $62.50 in court costs. Under the state consumer protection law, plaintiffs can sue for the amount of the damages, or $100, whichever is greater. A hearing on the matter had been scheduled for today in small claims court in Monroeville before District Judge Jeffrey Herbst.

Mrs. Bach, a self-styled consumer advocate who has been fighting against retail scanner and pricing errors for 25 years, said she went to court because she wanted to force CVS to fix the problem so other customers were not overcharged. The Monroeville store had refused to sell her the converter boxes without charging sales tax, she said.

"We all need to know our rights and to stand up for ourselves," Mrs. Bach said.

Americans with older TVs that do not have built-in digital tuners will need to buy digital converter boxes when TV stations switch from analog signals to broadcasting in a digital format. Most stations have agreed not to make the switch until June 12, although some already have done so.

TVs connected to cable, satellite or other pay TV service do not need converters.

Households can receive up to two $40 coupons from the government to use toward the cost of converter boxes. To apply, visit www.dtv2009.gov or call 1-888-388-2009.