The ubiquitous plastic bag

To me, the most stupid thing I've heard recently is the rush to stick a price tag on a plastic bag at my local supermarket.
They claim it is to make shoppers buy more expensive bags which are curiously named, "Bags for Life"!
Whose life, I ask, mine or the darn shop's life?
They can't fool me, this is not really a concern for reducing the use of the bags, but rather a cute way to make money.
There is a frighteningly easy way to ensure used bags do not end up in landfill.
If the shop puts its name on the bag and then charges the person 10p to purchase it, wouldn't it be a very simple task to advertise that they would pay 5p per bag to anybody who brings one into their place.
Like in the 'good old days' of yore when there was a deposit on bottles, children would delight in collecting as many bottles/bags as they could carry to supplement their pocket money.
Turn bags into valued commodities and they would completely disappear from all the rubbish bins
Plus, the darn shops would have spend some of our precious cash which we paid them for the blooming bag in the first place, in disposing of the offensive item.
When, many, many years ago I was a young lad, my Mum would pack me off on a shopping trip with a string bag in my pocket.
Shopkeepers in those days wouldn't ever dream of giving you anything to carry your purchases home with you.
Simplest way to get rid of the plastic bags is just to stop supplying them.
I have tried, unsuccessful, I hasten to say, to buy one of those string bags of my childhood.
Anybody out there in the internet world know where I can get one?