From the cheap old wrecks I've owned, I'd say the Fiesta is the most reliable and cheapest to fix. Escort comes next. Never owned a Vauxhall, but I believe they're similar. The two Metros I had gave good service - not many left now I think.
I try to avoid foreign cars - they always cost more to insure, though you can get cheap pattern parts for them from specialists.
French cars are weird, but I had a Citro�n AX which gave no trouble.
Japanese makes can be very reliable until they get old and then everything seems to go wrong at once (according to legend). I had a Datsun once which lasted remarkably well.