Claire Kierczek pretended to represent the Royal British Legion to steal full tins of donations in Coventry last November.
The 32-year-old used a fake ID to steal two tins from an Asda branch in Coventry, one of which contained around £200. She also stole £50 worth of cash intended for the Air Ambulance from a separate shop in Coventry.
Miss Kierczek, who lives in Dudley, is a known heroin addict and committed the same offence in 2015.
Recorder Christopher Donnellan QC has given her a 12-month suspended sentence and fined her £1 for breaking the terms of her two-month suspended sentence from last year, when she stole and sold a camera.
He avoided sentencing her jail to give her the opportunity to beat her drug addiction, but also sentenced her to compensate the Air Ambulance £50, and £75 to the Royal British Legion.
He said: “People who give to charities in boxes in shops often give small amounts because that is all they can afford to give. It is often those small amounts that make big differences to charities.
“People who steal from charities in this way undermine confidence in them.
“This is your last chance, and I hope you take it.”