Unsure about the cost of this procedure as every vet charges different prices.All vets have to sign a government form when euthanising any animal in Turkey as there are strict guidelines for this.If your animal has no quality of life and is in pain and suffering you will be asked if this is your decision,the vet will not actually make the decision for you.Because you have already undergone treatment for this cat and it has not recovered I am sure the vet you chose will euthanise it.Such a sad time for anyone who has to make this decision,it is never easy but take heart in you are doing the final kindest act any responsible animal lover can make for a treasured pet.Thankyou for caring.