A homeless man forgot he was carrying the synthetic drug mamba when he was arrested in Mansfield.
Tyson Clark, 26, was arrested for another matter, at midday on November 15, and searched at the police station, and the drug was found in a moneybag.
He admitted possessing the Class B drug, when he appeared at Mansfield Magistrates Court, on Thursday.
He was last before the courts in 2016 for shoplifting, said prosecutor Robert Carr, but had no previous convictions for possession.
Donna Pursglove, mitigating, said: “There’s a very long history of offending. He’s had a number of issues in the past that have led to custodial sentences.
“He is not a regular user of the drug.”
She said Clark had no birth certificate and this had prevented him from making a claim for benefits.
He was fined £80, and ordered to pay a £30 victim surcharge and £85 costs.