Trupanion has a page on their blog entitled "Claim of the Week" and it appears like there are over a hundred examples of claims they have paid.
Their policies have a 10% copay. Pet owners can choose a deductible between $0 and $1000. This allows you to manipulate the deductible to get a premium within your budget, but since Trupanion doesn't pay for examination fees and the deductible is per-incident, most pet owners try to keep the deductible as low as they can. As you peruse these claims, notice how these factors affect the reimbursement the pet owners received.
We all can learn from these claim examples because they aren't theoretical, but real events that happened. Sometimes we tend to think, "That would never happen to my pet." I'll bet these folks are glad they were prepared and had insurance when these unexpected events occurred.
Afterall, health insurance isn't just for people anymore!