Officers are investigating after a man used counterfeit banknotes to buy electronic goods advertised on Gumtree.
Avon and Somerset Police said it was aware of two incidents in Bristol which happened at the end of January.
The force said the man contacted the seller to ask them what the lowest price for the item was, before arranging to attend their home.
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When he arrived, he distracted them while counting out the fake notes and then left with the items.
A force spokesperson said: "We’re asking people to be vigilant after incidents in which a man has used counterfeit banknotes to purchase electronic goods advertised on internet trading sites.
"We’re aware of two incidents in Bristol in which counterfeit banknotes have been used to pay for expensive items advertised online. Both incidents happened on Friday 28 January – one in Clifton and one in Knowle.
"The man contacted the seller to ask them what the lowest price for the item was, before arranging to attend their home. When he arrived, he distracted them while counting out the fake notes and then left with the items.
"The offender is described as mixed race, around 6ft, of slim build, with black curly hair.
"He kept his face mask on throughout. He arrived on foot, but may have had a car parked nearby."
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