Best car for fuel economy that doesnt cost a bomb??

[Clarabumps]

I'm wanting rid of my 1.8 mondeo as it's inhaling petrol. I want a smaller car but one I can still fit a buggy in the boot. Any suggestions? I need practical advice on what one to get as I keep looking at whatcar reviews and my mind is whirling!
Thanks!xx

I have a 2009 Ford Focus 1.6 Diesel. (DH has the Mondeo). It only costs £35pa road tax and has really good fuel consumption. Plenty of room in the boot too. :)

I have the Ford Focus 1.9 Diesel ghia. I get 45mpg normally, and up to 55mpg on the motorway. Gigantic boot.

Mine's the saloon shape not the hatchback but I can get tons in the boot with or without the split back seats down.

I've got a Skoda Fabia 1.9 diesel, I get on average 67 mpg out of it. I love it so much!