I'm looking for a short story published before 1985 (I think) and likely included in an anthology (Hugo, Nebula, Sci-Fi Oddities).
The story is "Rundown" by Robert Lory, first published in If, May 1963 (available at the Internet Archive), reprinted in the 1966 anthology Science Fiction Oddities edited by Groff Conklin.
From what I recall, the story is about a a man who is desperately seeking a dime from passersby.
A dime. One dime!
He enters a bar and asks anyone if they could spare a dime, not ever giving the reason for his need.
"Please, a dime, I need a dime, that's all I—"
"A dime?" George laughed. "For what, a cup of coffee? This is a high-class place. Beer costs fifteen cents here."
Shorty joined in with a snort. "Maybe he wants to call his girl."
"I need the dime," the man said, leaning on the bar for support.
"A matter of real life and death, huh?" George said.
"Yes. Look . . . here. I have two cents, you take them."
Pete looked suspiciously at the two coins. "We don't sell anything that costs two cents."
"You take the two cents, but give me a dime. Please."
In the end, he keels over dead.
Not dead, but he is knocked out by a punch:
George needed no warning. He had seen the man eying his money, and he had hoped for just such a move. With a right fist to the side of the man's head, George took revenge for a bad day's work.
The man lay very still on the floor.
The long coat he is wearing flips up to reveal a slot in his back - a place to insert coins.
The coin slot is in his chest:
"Holy cow," said Shorty. It was the first sound any of the three had made after the man had left, fifteen minutes before.
George stared into the mirror behind the bar, seeking some mighty truth in his own reflection. "He says . . . he says Unbutton my shirt, and then . . ."
George fondled some coins in his hand. "Then he takes that crazy dime, a plain old, regular, crazy dime . . ."
Pete poured himself a Scotch. "What kind of guy is it, anyway," he said, "who walks around with a slot in the middle of his chest that he puts dimes into?"
"Yeah," said George, "and who ticks, yet?"