SOLVED. Classic book where they send a kid to buy several items and give him a penny and tell him he can keep the change?

[Stephen]

I'm having a senior moment. I just KNOW that I read this in a classic book that I re-read sometime in the last decade but I cannot recall which one.

I think that they sent the kid out with a penny to buy some paper, some ink and a pen and told him he could keep the change from the penny they give him.

Can someone refresh my memory?

[Stephen]

Solved it myself!

Bram Stoker's Dracula

Chapter 20
...If you can give me a envelope with a stamp on it, and put yer address on it, I’ll find out where Sam is to be found and post it ye to-night. But ye’d better be up arter ’im soon in the mornin’, or maybe ye won’t ketch ’im; for Sam gets off main early, never mind the booze the night afore.”

This was all practical, so one of the children went off with a penny to buy an envelope and a sheet of paper, and to keep the change.