Looking for Advice buying ProZinc

We are going to need to get more ProZinc for our fur baby soon and I have been looking for better options then our local vet. The bottles of ProZinc cost $116 from them. I was hoping to find something cheaper online. Does anyone have any Suggestions? The cheapest I have found is petvaluemart.com for $94. Dose anyone know if they are safe to get from? Anyone know of somewhere better? We love our Wibble but we need to try to keep it as cheap as we can. We have 3 cats other than her and one of them is also special needs.

 

Be sure to check on the shipping charges. My vet doesn't carry Prozinc, so I have to get it online. $116 is less than what I pay with shipping.