Well, that's not my case really, I am really lazy in what concerns to carrying plastic bags. I don't pay 5 pound cents though, I pay 2 euro cents and that's less, so it's a really small value for me to be carrying plastic bags everyday in case I go shopping.
I'm the same way, I have a plastic bag in my kitchen that's full of other plastic bags, he must feel like the king of bags I have a hard time just throwing the plastic bags away, I know how harmful it is so I always try to put them to some use.
From where I live, were forced to use paper bags, you can't get any plastic bags anymore. Even if you ask for plastic bag they'll just give you an extra paper bag and the worst part is that there are no handles! But thank goodness we did stash plastic bags in our basement so whenever we shop we just carry a few.
Where do you live death? That is a radical solution, but a good one. If they do want to be ecological, just ban the plastic all the way and don't put a price in it. Sure, putting a price in it makes us use less bags, but that's not their concern, they just want us to buy them the bags.