At about 12pm on Friday a man, described as in his early 30s, approached a property in the Bognop Road area of Essington, South Staffordshire.
It is believed he, and a second man, were in a green tipper van when they arrived.
He knocked on the door and told the elderly victim he needed to access the back of the property – asking her for £85. The victim, believing he was from the housing association, gave him £50.
A quantity of other cash was also taken before the men left.
People are being urged to remain vigilant and to report any suspicious persons or vehicles.
If anyone saw or heard anything suspicious in the area at the time of the incident, has CCTV that covers the property, is urged to message Staffordshire Police on Facebook or Twitter quoting incident number 356 of 16 July, or alternatively contact the independent charity Crimestoppers anonymously on 0800 555 111.