Mr K was accused of selling balloons filled with nitrous oxide – or laughing gas – to revellers at London’s Lovebox festival.
Police found him with 57 metal canisters used to hold the gas, dubbed ‘hippy crack’, and a number of balloons used by punters to inhale the fumes.
When asked if he was selling the so-called legal high, he reportedly told officers: “Yes, I am.
“I’ve got loads more in my bag and also about £200 in cash.”
Mr K was arrested and charged with possessing a psychoactive substance with intent to supply.
Stuart Miller Solicitors represented Mr K, who was found guilty at trial, and helped persuade a judge to show mercy.
A spokesman said: “Mr K denied having intent to supply the nitrous oxide and stated that the sole purpose of having possession of it was for his own personal use.
“The defendant disputed the comments made by the police officers at the scene regarding him supplying the nitrous oxide. He stated that the £200 cash found on him was money for food, drinks, travel and for general spending at the festival.
“Unfortunately, the defendant was found guilty at trial.
“However due to our strong mitigation on his behalf we were able to avoid an immediate custodial sentence and instead secured a four-month sentence, suspended for 18 months.”
The casings of nitrous oxide are meant for chefs who use it to whip cream when making desserts.
While the drug is legal to possess – but illegal to sell to under-18s – it still carries huge dangers and was blamed for the deaths of 17 people between 2006 and 2012.