I think you'll struggle to find an X1/X2 at that price...

There are usually a goodly supply of round column machines on ebay, typically the Warco MD30/Clarke 25 which usually have a bigger table than the X1/X2 for around £300 - £400. The dovetail columns rarely appear...

Not sure how big an X0 is, but have you looked at Amadeal's range of machines? I'm sure there's and X1 sized one for under £500 new...