A frame ball joint is cheap but can be an arse of a job to get in/out.
Under 3k.

2-2.5k but id angle at 2 for that motor

It having done 200k+ miles, I would expect it to be more than just the A-frame, rear diff is probably sloppy, gearbox output shaft also probably worn, rear half shafts, drive flanges etc -- a small amount of play in lots of areas along the drive train add up to lots of 'shunt', which translates to a big 'clunk' when letting the clutch out and changing gears.

Most that I have driven have had this clunk, some worse than others. It can be avoided entirely with careful handling of the clutch, but isn't ideal.

Well by the sounds of it I'll be going with my gut and waiting for a while.
Sounds like there could be a lot of work needed on this one. (on the other hand there might not be)
The couple I have driven have that clunk too but none half so bad as this one was.
As this is the first I've seen (with a view to buy) I'll keep saving and keep my eyes pealed without worrying too much.