I get a prescription for my cat's medicine - he has an overactive thyroid and I can buy the liquid medication on-line (I buy it from a company called Viovet) for about £53.00 per 100ml, it cost me over £80.00 from my vet. They charge me £10.87 for the prescription and I scan it and send it by email with the order. Shop around, I'm sure you'll get it cheaper than your vet.