When you see a new book by Mr.Kipling, you are ready to 'separate yourself from one fifty' because he 'has the goods with him.'" G.Selden suppressed an involuntary young laugh.
"One dollar and fifty cents is usually the price of a book," he said.
"You separate yourself from it when you take it out of your clothes--I mean out of your pocket--and pay it over the counter." "There's a careless humour in it," said Mount Dunstan grimly.

"The suggestion of parting is not half bad.

On the whole, it is subtle." "A great deal of it is subtle," said Penzance, "though it all professes to be obvious.

The other sentence has a commercial sound." "When a man goes about selling for a concern," said the junior assistant of Jones, "he can prove what he says, if he has the goods with him.

I guess it came from that.