Toronto Mayor David Miller's "One cent of the GST" campaign may end up costing the city money.

The Royal Canadian Mint says the city used the image of a penny in some advertising without prior consent.

The mint says the city failed to get permission or pay a required fee to use the image in a campaign designed to wring tax dollars out of Ottawa.
  
The mistake could end up costing the city a few thousand dollars in legal and royalty fees, reports say.