BBC News
https://www.bbc.com/news/uk-politics-49185007

It's kind of amazing what a 5p charge does.

They say the average is down by 130 bags/year or GBP 6.50/year per year or about $7.88 so just about 0.02 per day (rounded, it's the same in both currencies roughly). Interesting that an amount that small has such a huge effect

It shows the difference between thinking about something and not thinking about it, rather than any actual budgetary constraint.