Very nice niche. I think you can sell it for up to $5000. The only hard thing is to find the right buyer.
I think $1500 would be a fair offer. I specialize in insurance websites and insurance niche pays high PPC revenue. You can get paid up to $10 to $20 per click. All you'd need is about 1 click per day. For insurance category, you usually get high CTR also, so you would not need more than 20 to 100 UVs per day. I checked your website, why not gear it towards auto insurance? Place a quote box as the first thing you see when you enter the website. Maybe it is insurance for something else, but I am sure it will generate auto insurance clicks and people will enter their zip codes. If you do this and get some preliminary revenue figures, you will defiantly be able to fetch even more... The domain name alone is worth about $1500, a website done right geared toward high CPC would of course be worth much more with traffic and revenue stats.
Why would you think that? There are a shit ton of domains with the word insurance in them. Why would "instructor" insurance be worth anything special?