A disabled pensioner was charged £66,000 to have a driveway replaced with block paving, police have said.
Cheshire Police have revealed the case in a bid to warn residents to be wary of rogue traders in Ellesmere Port.
In another case the victim paid more than £50,000 to a rogue trader for basic maintenance work, much of which was never completed and the rest done to a poor standard.
Senior officers have said that some rogue traders had printed leaflets and branded vehicles to give the right impression when they approached customers.
Police have said many of those targeted are elderly and vulnerable.
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Chief Inspector Catherine Pritchard, of Ellesmere Port Local Policing Unit, said to the ECHO : “Unfortunately incidents such as this are still happening, with rogue traders targeting vulnerable people and trying to get as much money from them as possible.
“Rogue traders often appear to be highly professional. They can have printed leaflets and vehicles branded with their company name, making people think they are legitimate.
“They often use highly pressurised selling techniques to convince victims to use their services and charge exorbitant prices for work of a poor standard, or work that is never carried out.
“Enquiries in relation to these incidents are ongoing and we are committed to doing all we can to identify the people responsible.
“I also want to take this opportunity to urge people living in Ellesmere Port or anywhere else in Cheshire to be vigilant and to contact the police if they believe that a rogue trader is taking advantage of them or someone they know.
“Call us on 101 or give the details via https://www.cheshire.police.uk/ro/report, and also give the details to the trading standards department at your local council.
“I ask neighbours and family to look out for any elderly or vulnerable neighbours by checking on their welfare and reporting any suspicious activity to the police.
“I also encourage people to follow our advice on how to avoid falling victim to a rogue trader.”
Cheshire Police and Crime Commissioner David Keane said: "This kind of activity strikes at the very heart of local communities as those involved tend to target and exploit the most vulnerable in society. The damage and distress caused by rogue traders is despicable.
“As your Police and Crime Commissioner, I want to make it as difficult as possible for these type of criminals to operate in the county – I want to get the message across loud and clear that anyone who takes advantage of the elderly and vulnerable is not welcome in Cheshire.”
