Yep, cheap vans are now awful. Gone are the days of finding a Mk4/5 Transit with 6 months ticket and a floorpan mostly consisting of iron oxide for £500, that you just knew would serve absolutely fine because even the most ham-fisted, lead footed twat of a driver would struggle to blow the old 2.5 Di up. Same for old Renner Masters and Bedford CFs.
I got lucky with the Transit I had a few months ago, but to be honest cheap modern vans give me the fear now. In the shite end of the market, I'd want the most rust-free (or already had half of Port Talbot's yearly production welded in) early Mk6 Transit that I could find, with the 2.0 TDDi lump, and I'd have to budget at least £1500 (probably closer to £2k) to find one like that. Otherwise, I'd seriously consider buying nearly new something that has been looked after, and taking the hit on depreciation instead. Newer vehicles can and do go wrong, but spunking a decent amount on a looked after or new van that hasn't been thrashed and trashed by someone who doesn't own it and therefore doesn't care about the repair bills is a pretty decent argument against potentially forking out for injectors, clutch/DMF, gearbox, several miles of welding etc on an older van.