Just be careful you don't buy a
total shunter. You can make a bit of money fixing them up, but just make sure you don't get saddled with something thats unshiftable, or is going to cost you a fortune to fix. A lot of MOT failures / bangers are that for a reason, i.e they're ****ed or the owners would have fixed them and put them back on the road themselves.
That said, sometimes you can touch lucky. I bought a decent spec Xantia TD a couple of years ago with a suspected ****ed water pump / maybe a blown head gasket, and it turned out to be nothing more than a blocked thermostat, and still runs grand today
Got another Xant last week with oil in the coolant, which I was going to either do a head job on, or break for spares, but turns out it seems just the oil cooler has gone porous, sending oil into the water, but theres no water in the oil, so I may get away with just replacing the cooler, the head is probably intact.
Actually, depending on what happens with this one with the oil, I might flog the other one, which just needs a couple of tyres and a cleanup for the MOT, so if you're still looking it might make you a few quid.
A good place I've found for cars like that is Ads for Free, as well as the under £1000 section in AutoTrader. Ads for Free is the better of the two actually, I've bought a fair few decent cars from there that have required just a little work to get back into shape, one of my current crop of XMs being a very notable example. Paid £250 for it in there, its now worth 2.5-3k (not that I would sell her) after a wee bit of effort, not bad
Anyway, I'm waffling, just make sure you get something thats gonna make you a quick turnaround without being too much hassle / expense, if I see anything I'll give you a shout
Anyone got an n-mot'd car they're selling? 
