The Maxi Cosi CabrioFix is possibly the most popular 0+ car seat going but the rather handy ISOFIX base usually costs more than the seat!!
Mothercare - £105.00 delivered
Toys R Us - £104.99 delivered
Boots - £102.76 delivered
Tescos - £99.99 delivered
Halfords - £92.99 instore or +£4.99 postage (currently £83.69 with 10% sale)
Very - £82.50 delivered (though they list 2 of them, one at £115 so who knows what this is!)
We've already got one of these in my wife's car and I was looking for another to go in mine so have just ordered :)
To confirm, this is the ISOFIX base EasyFix, not the non-ISOFIX EasyBase. It really is well worth the money as it's sooooooo easy to quickly and safely get the seat in and out of the car.