I agree that pet insurance can be a waste. But I worked with a woman years ago that had some plan that she paid about $15 a month. It gave her discounts on the normal vet bills and did cover about 10% of other stuff. Her dog had surgery when it got hit by a car and the bill was over $1000. I think she paid about $10 for shots so she figured it was worth it. You really have to weigh the pros and cons of it before taking it.
Personally, if I had a dog, I would look to see if it was predisposed to any problems based on the breed and decide from there. I would probably choose to deposit the money into an account if the cost is high. Also, I have taken my cat to Petsmart for shots since they are cheaper. But for other things I would take her to a regular vet.