I’ve been checking the NADA online guide for various boats and it’s hard to make sense out of them.  For example, I looked at a 1996 Bass Cat Eyra with a Merc 175.  The suggested list price was $12,824 and the average retail price was between $5,000 and $5,730.  
 

Just not sure what to think.  I’ve seen this with a lot of boats.

Take it for face value. Average retail is just that, average. What I would look at is overall condition of the hull, motor, and trailer in the average retail price. Don't bother with the other filters. Then, find out from the seller about the age of the add ons. Trolling motor, electronics, power poles, batteries, trailer tires etc. If they are 3 years old or less, I'd add 50% of the cost of those items on to the price. So, if it has a $3k Ultrex, I'd figure $1500 on top of the average retail. $1500 graph, add $750. and so on. If the add ons are more than 3 years old, I'd be hesitant to add much onto the retail price unless the condition is immaculate. 

 

Buying a 25 year old boat, I'd make a deal contingent on a shop giving the boat/motor a once over and split the cost with the seller. I'd much rather be out $150 knowing ahead of time the boat was a dud, then out 7 grand and being stuck with a problem child.

Nada should get you within 75% of the actual value.