What the others said plus a few more things - get an on-water test and run the boat. When doing the on-water test, make sure it gets on plane nicely and handles smoothly. Check out EVERYTHING to make sure it works. Livewell, bilge pump, lids/locks, lights, tilt/trim, motor, depthfinder, etc. When you pull the boat out of the water, pull the plug and make sure the bilge stayed dry. If it did, this is the time now to check the bilge pump by plugging and adding some water to see if it works. It won't hurt the boat and a serious buyer should allow you to do it. Still have the compression check done and have him change the lower unit fluid in front of you check what kind of shape its in (should look like oil fresh from the bottle with no excessive metal shavings or cloudy/milkly fluid).
If its really in good shape, $7,500 might be about right. Check on your local ads or craigslist for your area to see what comparables are going for.
Don't forget to check out the trailer - how do the tires look? Grease spatters behind the back of the wheels (bad - probably means a blown seal). Galvanized trailer or painted? If the latter, is there rust? Do all the lights on the trailer work? Swing away tongue? Brakes?
Definitely make sure all titles/registrations/etc. are in hand and check the laws of your state on what needs to be done to transfer title to the boat AND trailer (oftentimes they are considered separately - sometimes the motor requires its own title too!).
Good luck!
