Q: I’m trying to find a short story in which an spaceship runs out of fuel on earth. The aliens on board seek nickels for fuel and are willing to pay for it with a wonder creativity drug. Humans who ingest the drug have an explosion of creativity. The drug turns out to be alien fecal matter which led to the punchline: it was really good shit.
A: That was “Pipe Dream” by Chris Miller from the June 1972 (Science Fiction) issue.