Just run some figures through excel, used an average MPG figure to calculate cost of fuel per month (I was surprised to find that I should actually only paying about £185 for fuel, so I'm budgeting £40 more than I need to, thanks to the recent drops in fuel price).
I reckon I could be saving over £90ish a month by buying a small run-around.
Plus based on savings alone the two small cars would pay for themselves within 2 years.
Of course I haven't taken servicing and maintenance into account, however I can't see them being any more expensive than the Clio.