Our son bought a 1972/3 Ranger 29 last year, it had been reasonably maintained and upgraded over the years, and surveyed well. He was able to buy it for something less than $9K US. It has a FWC A4, runs like a Swiss watch, quiet and smooth.
In the past year he has upgraded the sailing hardware (his choice, the old stuff was dated but functional), sold the radar(!) to me, replaced all the windows/ports (typical task for a boat of that vintage) and cleaned up and repainted the chalked deck.
None of these chores should be considered excessive when buying in that range, and none are too difficult or costly to do.
In the end he has a perfectly serviceable boat for the area he sails in, it's sound and did not break the bank. If you go into these deals with your eyes wide open, and with a good surveyor you can do well.