You don't say what engine you have but assuming 1.8 K-series then yes you can pick them up BUT it's that dreaded head gasket again so maybe one with a warranty would be a good idea. You can also fit one from mg rover cars but I believe you'll have to swap over the sump. Also I believe earlier engines used a distributor whereas later don't though folk on here have said that you can fit either but I assume you'll need to make some modification.
Oh, & check out ebay but they seem to start at around £250 & go upwards. I'd budget £500 for something decent.