Speaking as someone who worked in the insurance industry for several years, there is no "insurances" plural term that is commonly utilized in the business (Insurance, in and of itself, incorporates all types of insurance, and is both singular and plural.)
This noted, I personally managed to sell insuranc.com (typo missing "e") many years ago in the low $$$$ range (typos had more value back then...) So there is some value with this domain, but what really kills the name is the .biz extension. Honestly, I think you'd be lucky to land very low $$$. JMHO... Good luck!