Yuo could try Adtrader.co.uk it's the website of the yellow free ads paper, lots of cheap cars, search by make/model and the site will list them by distance so you can go and look at the local ones. very few pictures and free to advertise so you get a lot of rubbish advertised, but if you know a bit about cars it's worth trawling through for the bargains.
Of course there's always E-bay, better pictures, better desriptions and more back up info i.e. feedback, payment protection etc. but not always the cheapest and, in my experience you have to be prepared to travel further to get a bargain.
Good luck