Our three are all insured it costs me £18 per month for the three of them. Their covered for everything apart from booster injections, yearly check ups and stuff like nail snipping.
Last year when Dan was getting lots of bites (we think from Bagel!!) they all turned Yucky and needed lots of treatment - the insurance saved us a fortune - we have to pay the first £50 of any treatment they need - but if it's an ongoing complaint we only pay that the first time all the other claims are paid in full.
We also had our late cat Kisi (RB) insured and that again was worth it - especially at the end of her life.
Don't forget all this information pertains to UK - not at all sure what it's like in USA.

Lynne