Yes, Mr B saith soothly Bill. I quoted the basic site ref without checking the exact location of any resource - sorry.

FWIW, I had wondered if it could relate to the old habit of placing pennies on the eyes of a corpse - so that would be the last coin 'paid' by anyone, giving a meaning something like "I'll be dead before I pay full retail price for ~ !". However, I have nothing but surmise to base it on!