As we have found to our cost there are liars, there are d****ed liars and then there are people selling boats. We have looked at boats described as being "sail away" and viewed rusty dirty junk. However I will say if you ask the BROKER the right questions they may wriggle a little they are almost always truthfull when you pin them down on something. We are always concerned about the condition of the standing rigging and before travelling out of our way to view a boat will quiz the broker on the state of the mast rigging and sails.
The asking price may have no relation to the real value of the boat. It is not uncommon for the owner to decide initially to recover the money they have in the boat or what they owe the bank!
After a year or so reality sets in and the price comes down. I have been following an Endeavour that started at 130k and came down to 84k on Ebay. It is now sold who knows what for.
There is no way round actually looking yourself [or by proxy] and decide what is useable and for how long. I have been looking at one boat where the owner proudly lists a large battery bank in excellent condition [ purchased in 2000] Hmmmm 9 years old batteries? It needs 6 at 250 dollars each.