Cheap runabout?

[The MaDDeSTMaN]

I'm thinking of getting myself a cheap runabout so I can drive that around while I get a whole stack of things fixed on my Mk II 2.0 Escort.

I'm after a car that doesn't cost much more then $500 & is cheap to run, I don't care what it is, as long as it gets me around and doesn't cost much in petrol each week. I don't care if it looks like crap, as long as it runs, because the car I care about is my Escort, not this runabout I'm considering getting.

Any ideas what I could get that meets that criteria?