In 2015, England levied a 5-pence plastic bag fee that retailers with more than 250 employees had to charge per bag. Initially the fee led to an 85 percent decrease in the use of plastic bags. Now, Mark Hall from U.K.'s Business Waste says the 5-pence fee is "no longer a shock to the system it was once was" based on a poll of nearly 2,000 shoppers from a wide range of stores.

When the 5-pence fee was introduced, 84 percent of those polled said they stopped using plastic bags and 16 percent were still using them and paying the fee, which is the equivalent of 7 cents. Now 24 percent of those polled routinely pay the charge when shopping, and another 38 percent say they pay it sometimes. Only 36 percent are still unwilling to pay for bags.

"It's clear that we're backsliding on our shopping habits, and the main reason is that we no longer care about adding a few pence onto our shopping bill," said Hall.

Business Waste's suggested solution is "to hit shoppers in the pocket" with a fee that would make most shoppers feel the cost is worth bringing their own bag.

When asked what's the most they would be willing to pay for a supermarket bag, shoppers gave these responses:

  • Nothing: 3 percent
  • 5 pence (7 cents): 16 percent
  • 10 pence (13 cents): 23 percent
  • 20 pence (26 cents): 38 percent
  • 50 pence (66 cents): 14 percent
  • 1 pound ($1.32): 6 percent

Business Waste is calling for the fee to be increased to 1 pound, the equivalent of more than a dollar, to put pressure on shoppers to make them change their habits. Business Waste would like to reach a goal of zero plastic bags used.

A smaller fee, they say, would "leave people in their comfort zone where they won't miss the money."

When is a fee too much?

This got me thinking about my own comfort zone. I live in New Jersey where there is no plastic bag fee. I have a small cabinet full of reusable shopping bags that I always take to the store when I'm doing my weekly large shopping trip. I also do my best to grab a couple bags if I know I'll be stopping by the store at some point in the day for a few items. But if I forget to grab the bags I'll still shop and take a plastic bag or two.

I save those bags and definitely reuse them at least once, but I'm wondering what fee would take me out of my plastic bag comfort zone. It probably wouldn't be 7 cents if I only needed one or two bags. It might not even be 20 cents. Twenty-five cents may start to make me uncomfortable. Fifty cents would definitely make me stop. If I had to pay 50 cents for every plastic bag I used, I am sure I would be diligent in taking my own bags almost every time, even if I only needed one bag.

What is your plastic bag fee comfort zone? How high would a fee need to be to make you remember your reusable bags every time?

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.