How much does it cost to take a sick small animal to the vet?

A lot. Any trip to the vet is expensive. It depends on how sick the animal is. If it's more serious than what you had anticipated, the bill can go up to $1,000. If it's just a minor problem, the bill can be anywhere from $50-$100. It also depends on the animal. You should really be more specific with your question. A sick horse is going to cost a crap load more per vet visit, than say a bunny. It also depends on where you're taking your sick animal.