he puts a new, bitter spin on the idea of love, suggesting that most people treat it as a transaction, rather than a sacrament. The old man's cynicism is in contrast to the love-struck attitude of the man who's visiting his shop in search of a love potion: the youthful Alan.

Alan is desperate for an elixir to make Diana, the woman he loves, pine for him as ardently as he pines for her. Time and again, Collier highlights the radically different ways the old man and Alan view love as well as the potential effects of the love potion. For example, take this quote wherein the old man is extolling the virtues of the love potion to Alan:

"You will not have to use your imagination," said the old man. "And, by the way, since there are always sirens, if by any chance you should, later on, slip a little, you need not worry. She will forgive you, in the end. She will be terribly hurt, of course, but she will forgive you—in the end." "That will not happen," said Alan fervently. "Of course not," said the old man. "But, if it did, you need not worry. She would never divorce you."

Note the way the old man presents the love potion as a tool for manipulation. So great are its powers, Alan can use them to his advantage to get a free pass for infidelity. Of course, idealistic Alan finds the very idea preposterous for now; however, the old man's cunning tone suggests that this is inevitable.

Throughout the story, the old man also tries to pitch another potion to Alan, one which does costs five thousand dollars, which he euphemistically calls a "glove cleaner." The potion is a poison, of course—a "life-cleaner." But why would the old man champion a powerful poison to a youth looking for a love potion? The answer lies in the old man's statement below:

"I like to oblige," said the old man. "Then customers come back, later in life, when they are better off, and want more expensive things"

The sinister implication is that there will be a time in Alan's life when he will be back in the old man's shop, ostensibly for a poison for Diana to undo the effects of the love potion. His love for Diana will fade, and her ardor for him will grow oppressive. The expert salesman that he is, the old man is making sure Alan remembers the second potion: the chaser.

In drinking parlance, the chaser is the second drink you consume after a shot of hard liquor. The chaser of the title is at once the second sale the old man will make to Alan, a "life-cleaner" poison, as well as a vindication of the old man's skepticism about love. The old man also seems to be offering a warning to Alan: a love borne of enchantment or earned through less-than-ethical means can never come to a happy end.

The quote you're referencing is a line in John Collier's short story, The Chaser. 
The story is about a young man named Alan who meets with a mysterious old man in order to buy a love potion that will cause the woman he loves, Diana, to love him back. 

However, before showing him the love potion, the old man hands him a bottle of poison he sells for $5,000.00 and tells him that it's colorless, tasteless, and won't be picked up by an autopsy.

Alan then tells him that he's not looking for a poison and asks if all the other potions are as expensive as that one. That's where the quote you referenced comes in. 

The entire quote actually reads, "'Oh dear, no,' said the old man. 'It would be no good charging that sort of price for a love potion, for example. Young people who need a love potion very seldom have five thousand dollars. Otherwise they would not need a love potion'" (Collier). 

In saying that, the old man is implying that if the young man had money, he wouldn't need a love potion in order to get the woman he loves to return his feelings. If he were wealthier, she'd show him affection for that reason alone. It's also an implication that the young man doesn't have much to offer the woman, at least in a material sense.