Excellent idea to get a pre-purchase inspection done. If the owner has tried to adjust the steering box to fix the play, then he's probably trying to mask front suspension problems. If it hasn't been done, then expect to spend well over $1000 to get it completely rebuilt. And you may need a new steering box if he's already adjusted it to the max. The rear clunks are likely the sway bar links already mentioned, although it is likely that you'll need the rear end rubber replaced. Maybe shocks too. Could get very expensive if you don't know what's wrong for sure.

Len