I had been looking for a used Insight for a bit, and knew I wanted to spend less than 15K for it. If you buy it untitled, you can have some tax incentives, but dont know if they're over after 2003 or not. I looked around for used ones and they ranged from 12K-14K for models 2000-2002) which had 35K-more on them. For ones in the NY Metro area, I found mine for under 11K and 27,000 miles. (With A/C, BTW) I bought mine this past weekend and LOVE it. Just going to upgrade the Stereo and Speakers.
I'd go for it, you have a nice warranty with it, and if its a CVT, then its more of a savings. I purchased a 5sp since I wanted to milk more mileage out of it. I dont have a long commute, but I travel a bit to see family and friends, and 15MPG on a SUV was too much for me.
Hope that helps. I Averaged 54MPG on a 200 mile weekend learning how to drive it, both in hilly and highway miles.
Michael