Are you in the US?
I have a $200 deductible (per condition) for both of my boys with PetPlan. After that, insurance pays 100%.
That said, depending on what company you are going with you might also be able to adjust the co-insurance to reduce the amount that the insurance pays after your deductible - that could save you more money on the premium, since it is less risk for the insurer. I just feel better knowing that if a really big expense comes, I just have to pay $200 and the rest will get reimbursed by insurance.
(a.k.a. Lucky's & Sparky's mom!)