[RedDevil]

Getting them down below forty mpg takes a lead foot or adverse conditions (mountains, short trips). My commutes are about 60 mpg year round, but I also do the occasional shopping trips etc. around town so I end up about 5 mpg worse than I would if just commuting ecomodder style.

A 192.000 mile insight probably needs 8 new spark plugs soon, which are expensive and cumbersome to change (the back 4 are only accessible when you remove a cover under the windscreen). The 12V battery may be bad, it is a known weak point. Changing the CVT fluid if you have no guarantee that has been done recently with the right fluid is important too.

For the rest these are reliable cars, of the 'I don't love it but it does the job' kind. There are Insights around with a way higher mileage. It should be good for quite some years and miles, so $3,000 does not seem overpriced.

That he had to swap the hybrid battery worries me. The Insight generally tends its battery well. What can damage it is prolonged exposure to temperatures over 55 degrees Celsius (131 Fahrenheist), like if you park in the full sun. Bear in mind these cars vent their battery with air drawn from the passenger compartment, so if it is blazing hot and you start the car without first letting the hot air out it will start frying its battery initially. Especially because the dash has the tendency to get blazing hot too, and the first two minutes you run the fans it spews out extremely hot air.
In such conditions I lower the windows and let the fans blow until the air gets better. If I have time I won't start the car yet, otherwise I drive off with all open until I hit the highway, then I run the A/C until we're down to normal.

Could be this owner did not take sufficient care with the battery? Then in what condition will the replacement battery be?
The Insight will run without the IMA battery power, but it is a regular pig then, especially slow on initial acceleration.

The 2nd gen Insight shares its chassis with the Fit. If you want a practical, reliable and reasonably economical car without having to worry about the hybrid battery get a Fit.
Pity the manual Fits have short gearing.