That is awesome and very interesting @exyle!

In South Africa we have added costs to our plastic grocery bags ('bout 50c) and although it's not expensive per bag, you quickly end up collecting bags, even though we can't get refunded for it.

In a similar fashion, we tend to keep our plastic containers - margarine tubs, yoghurt jars, ice cream tubs (and even sometimes plastic bottles too!), as these are certified to be microwave and dishwasher safe, which leads to saving on container budgets!