Courier job on self employed basis?

I contacted a firm on job vacancies advertising for courier drivers,self employed basis,and owning a van or car,they wrote back saying they want �75 up front before they can give me any work,this is to cover their advertising costs ,a bank account number to send my money to etc. How safe is this ? I really need the work but can't take a risk,they said I'd get plenty of work through them.