If you're only keeping the car for a year, it has a full years' test, and the price is low enough, I'd be inclined to go for the rusty heap to be honest, as long as it's mechanically sound.

You're looking for a reason a car is very cheap -- rust isn't something that's likely to cause you any grief for a year (although it'll slap you come MOT day) and it's better than a shafted engine.

If you want to keep the car longer, of course, none of this applies.

I'd be looking Korean if you're wanting cheap to be honest. Newer car = better shot at getting a good one IME.

I had a 1.6 P10 .. 35 - 40 mpg general running around, 40 - 45 mpg on longer runs, excellent car, generally relaible, sold after 10 years at 173,000 miles - original clutch, radiator etc - only sold it because I want a more modern car with aircon / airgbags etc. Now have a P12 2 litre Primera, lucky to get much over 32 mpg on a run, loaded with toys but much more expensive to run.