People in some of the poorest parts of the country are having benefits paid directly onto pre-paid Mastercards.
The card companies are charging them to have the money paid in, to take out cash, and often a regular fee as well.
But a leaked email from the Department of Work and Pensions, seen by this programme, shows that DWP staff fear many customers do not realise the costs associated with having their benefits paid onto these cards.
When DWP staff in Clyde and Fife contacted customers to ask if they were aware of the charges on the cards, they found the majority of the customers were not.
Presenter Paul Lewis hears from consumer campaigner Mike Dailly.
This item was first broadcast on Radio 4's Money Box on Saturday, 23 January 2009