The 5p charge for a single-use carrier bag doubles to 10p from today – and it is now going to apply to all businesses in England.
Previously, only larger companies with 250 employees or more had to apply the charge.
Statistics from the Department for Environment, Food and Rural Affairs (DEFRA) shows that since the 5p levy on plastic bags was introduced in England in 2015, the number of single-use bags distributed by large supermarkets has fallen by more than 95%.
The average person in England now buys just four single-use bags a year, compared with about 140 in 2014.
At his convenience store in Sheffield, Stuart Reddish, president of the Federation of Independent Retailers, told Sky News: "We’ve been pushing for this for the last six years and now we’ve finally got a level playing field that we can actually do this.
"A lot of smaller retailers do make a charge already, and that money goes into local charities.
"It’s about being eco-friendly. We’ve seen how plastic can devastate the oceans, and cause massive problems for landfill. I just hope the customers understand why it’s necessary."
Research suggests they do. A survey in December for waste and resources body Wrap found 73% of consumers supported the levy.
However, the same poll found that 26% of consumers still bought single-use bags at the till when shopping for food.
The government expects the use of single-use carrier bags will decrease by 70% to 80% in small and medium-sized businesses now the charge has been expanded.
Environment minister Rebecca Pow said: "Everyone wants to play their part in reducing the scourge of plastic waste that blights our environment and oceans. The 5p bag charge has been hugely successful, but we can go further.
"From today we will increase the charge to 10p and extend it to all businesses. This will support the ambitious action we have already taken in our fight against plastic as we build back greener."
Some campaign groups say the levy is not enough. Friends of the Earth is calling for stronger government commitment on plastic, including legally binding targets to phase out the use of all unnecessary single-use plastic products, as part of the upcoming Environment Bill.
Friends of the Earth plastics campaigner, Camilla Zerr, said: "If ministers want to get to the root of this problem, they need to take a tougher stand against all single-use plastics and support re-use and refill.
"For too long, government has allowed a piecemeal approach which is why targets that are legally binding are now needed, and urgently. It’s these combined changes that will stop wasteful plastic in the first place."