i use PC Health Pet Insurance, it was the cheapest (at full coverage) i could find.
it's about 45$ a month and i cannot tell you how i have been SO SO SO HAPPY and grateful with myself that i chose to invest in it. (heck minimal coverage started at just 20 bucks or so)
i have a Service Dog, so his health is of optimal importance as he is my medical equipment to keep me going basically.
He's only 2 years old right now, and has been counted with at least 24 (known)allergies (did the SPOT allergy testing thing), and is now on serum injections to try to help minimise his insane itching and stuff.
However, the choice to get the SPOT test done (it's nuts expensive) was reached only recently after many many vet trips since he's been around 6 months old with (unknown/unexplained/unresponsive) skin issues.
So, my bottom line.... if your pet is super important to you, find a pet insurance company that you can afford (theres lots out there) and DO IT!