Source: Pinterest
I suspect there aren't many of you who remember this.
When we were kids and would venture out to public places, our mothers would direct us to crawl under the bathroom doors
in order to save the dime.
And heaven forbid you came out of the stall and let the door slam shut! Even strangers would admonish you for that!!
I suspect that's where the expression "spend a penny" comes from in England - having to pay to use the toilet. (The first time I went to England I noticed many of the bathroom stall doors went all the way to the floor which would have made our "crawl" impossible.)
If this practice was ongoing today they would have install credit card readers since many people no longer carry change!