I don't have specific funds allocated, but we do have savings at our disposal.
All of our animals receive routine care and any time I add a snake to our collection I always budget for a vet visit when considering how much I am going to spend on the animal. If something unexpected comes up, we find the money.
My herp vet has extended discount pricing to me because I have a growing collection with an eye on eventually breeding. I work with him in that I try and bring my animals in groups (at least for routine care).
I too am frustrated at the number of people who apparently believe that health care for their animals (particularly snakes) is optional. On another site there was a post recently that basically asked "does belly rot cure itself or do I have to go to a vet?".
I felt like telling the person to surrender their animal to the nearest shelter/rescue.