An outright ban on plastic grocery bags is a mistake. It is not a simple black and white issue. All possible actions and consequences should be fully evaluated - such as the washer/dryer costs for reusable cloth bags, energy and transport costs for other alternatives.
I believe the solution lies somewhere between free bags and an outright ban. A five cent charge was a good start but it is not sufficient for mass behaviour change. Also some stores continue to provide free bags.
I believe the solution lies in "return it" - which is a successful program. I suggest a 25 cent charge should apply to each bag. You should get your money back if you return bags (for recycling). A 10 cent charge may not provide enough incentive to return them. The stores could build the cost of the program into their cost base.
Dave Bains, Surrey