My father had one that he used for years. I don't know why, but it stuck with me.

"I see", said the blind carpenter, as he picked up his hammer and saw.

There are dozens of sites about wellerism. Here's one:
http://www.utas.edu.au/docs/flonta/DP,2,1,96/WELLERISMS.html

Instead of saying something was going to be expensive,
a business man I knew said:"That runs into money, as the monkey said when he pissed into the cash register."