I looked into pet insurance once and decided that if one has just one or two pets, it might be a good deal, I have many so it is not.
There are some ways to reduce pet medical costs:
See if there is a local vet school. Often you can get very, very good care at minimal cost.
Learn to do some things yourself (I give my own immunizations to my cat/dog, except for rabies)
If there is no vet school, see if there is a large clinic; often they will have vet techs who can at least triage your problem and with their specialized knowledge at least advise you as to whether it is a minor problem or one requiring a vet visit.
Offer a barter: larger clinics are often enormously busy, if you are talking only one or two pets, they may be willing to trade vet services for phone or landscaping help or other services, you never know- and I would think any honest offers would at least be considered.