I just purchased a 2006 marlin with 32 hours on it, I paid for a complete survey. I also paid to have the engines compression tested by a qualified mechanic along with the printout on both engines (total hours, how many hours at what rpm, any fault codes, etc. The total cost for the work listed above was a little over a thousand. This also included hauling the boat, powerwashing the entire hull and relaunching the boat a few hours later after the out of water portion of the survey was complete.
To be perfectly honest, it was a waste of time and money. The only area of concern was the windshield wipers were worn and the first aid kit was inadequate. However, if i just spent my life savings and found out there was a expensive repair needed I would have been very upset. Kind of gave me piece of mind knowing everything checked out. Looking back, I would probably have done the same thing again. I always prefer having someone besides myself look at something before making a big (expensive) decision.
Assuming you want a full survey as listed above I suspect you are looking at around $500-$600. Add a few hundred for the engines by a Yamaha mechanic with the laptop and the software.
The hour meters on my boat were off by a few hours if memory serves me correctly. Not sure why.
Finally (sorry for the long post), I would certainly recommmend a survey. Pretty cheap 'insurance' on such a large purchase. Keep in mind I am the oddball that did both of my own home inspections, and I did not get a survey on the last three (much less expensive) boats that I purchased.
