Robert Minor, a Kansas University professor, has been using reusable bags for at least 10 years. Minor, who was shopping in May at Hy-Vee Food Store, said he has about eight bags that he received for free at various conferences.

Mandee Gieber, Lawrence, buys her first reusable bag at Hy-Vee Food Store on Sixth Street. Gieber bought a thermal one for .99 in May because it was on sale. She said she likely would buy more reusable bags to cut down on landfill waste.

It isn’t hard to figure out why using a reusable bag makes sense. There are tons of data on how unhealthy and costly it is to use plastic and paper bags.

Lisa Foster, founder of California-based 1 Bag at a Time, reminds shoppers that free paper and plastic bags are not free.

She said the costs were hidden in higher prices for other products and in higher taxes for landfills and cleanup costs.

She said cities spent up to 17 cents per bag for disposal. The average American uses about 520 bags per year. That adds up to $88 per person in taxes. New York City estimates that if each New Yorker used one less plastic bag per year, the city would save a quarter of a million dollars.

Foster offered more evidence of why people should ditch plastic and paper bags:

• The petroleum used to make 14 plastic bags is enough to drive a car a mile. The 380 million plastic bags that Americans throw away each year are made from millions of barrels of petroleum, adding higher costs for petroleum-based products like gasoline and energy for our homes.

• Littered plastic bags are an eyesore for humans and a deadly killer for wildlife. Just how deadly is a matter of debate among environmentalists and researchers. But Foster is convinced that in some parts of the ocean, there are six pounds of plastic for every pound of plankton.

“There is not a fish in the ocean that doesn’t have some plastic in its stomach,” she said. “The next time you order tuna, I guarantee you there’s dioxin in there from plastic that you think you’ve thrown away.

“We just think, ‘Oh, it’s just a plastic bag.’ But if you are an informed consumer and you understand the plastic doesn’t just go away, it comes back to us. It gets in our food chain. It gets in our waterways. It gets in our air.”

Get informed

Foster strongly encourages people to educate themselves. That’s because she was “duped” when it comes to paper bags.

“I’ve always been an environmentalist and I always picked those paper bags, but then I found that paper bags emit more global warming than plastic bags and I was horrified. I was so angry. I slammed kitchen doors for a week,” she said.

“I really felt like I had been cheated in some very basic way, and I went out of my way to get informed.”

Foster said the truth was that paper bags emit 70 percent more global warming gases than plastic bags in manufacturing and 50 times more water pollution. According to a number of environmental Web sites, Americans used 10 billion paper bags in 1999, consuming 14 million trees.

In 2005, Foster founded 1 Bag at a Time. The company sells reusable bags and promotes awareness about the impact of disposable bags.

She estimates one reusable bag replaces 1,000 plastic bags and saves the government about $170.

So far, business is good. She sold 200,000 bags in 2006, 2 million in 2007 and 8 million in 2008. She said the business has given her hope for our future generations.

“Sometimes, I have been very pessimistic about the world, about the state of humanity and where we will be in the future,” she said. “And then sometimes, like with this company, I am so optimistic about what people are capable of and the changes that people are capable of — even small changes can make a really big difference.”

Foster said she has heard the number of people using their own bags to shop is up 50 percent from the previous year.

Growing trend

That doesn’t surprise Lawrence merchants. Chris Wiltfong, assistant store director at Hy-Vee on Sixth Street, estimates there has been a 200 percent increase in usage since last year.

“It’s been very noticeable over the last year,” he said. “We sell a tremendous amount of them.”

Wiltfong estimated the store sells between 400 and 500 per week. Hy-Vee’s reusable bags cost about $1, and they recently began offering thermal bags for $1.99.

Last month, Lawrence resident Mandee Gieber bought her first reusable bag.

“It’s just the smart thing to do. All of my friends have them and they use them for multiple things,” she said. “I have so many plastic bags at home. You know, five minutes in the car and then forever in the landfills.”

Robert Minor, a professor in religious studies at Kansas University, has about eight reusable bags that he received for free at various conferences. He said he keeps them in his car and just grabs them before heading into the store.

“I don’t have to deal with plastic bags when I get home. I don’t have to worry about throwing those things out.”

Some stores like Hy-Vee and The Community Mercantile also offer incentives for shoppers to use their own bags. Both of the stores provide a 5-cent discount per bag.

Jacqueline Victor, general merchandise buyer for the Mercantile, said the store sold 2,400 reusable bags last year, twice as many as the year before. They sell an assortment of bags that cost between $1.29 and $8.

Victor said the Merc has been selling reusable bags for at least seven years.

“One of our main objectives here is not to just sell food, but to promote a lifestyle that is healthy both for the person and the earth. Reusable bags are just sort of a natural outlet of that,” Victor said.