Agents should all carry Errors and Omissions Insurance. Some FE companies require it so you just need to plan on buying it when you start contracting so you aren’t locked out of any companies that you may need.
There are all sorts of “discounts” through various carriers and organizations but none of them seem to have a much cheaper price than just buying it directly through E & O for Less. At http://www.eoforless.com you can set up a monthly payment and print your certificate out as soon as you pay.