My current cat, a 5 year old ragdoll's costs are:
£80 for a 10kg bag of Royal Canin Ragdoll food every 6 months or so which is around £14 a month.
£24 for cat litter, you could easily spend less though.
£14 insurance with Animal friends.
A pouch of wet food a day, no idea what that costs as I bulk bought the day before my previous cat died in January and still working through that.
£30 for vet plan which covers vax, flea and worm treatment and all consultations and a yearly blood test.
Treats like lik e lix and dreamies about £5 a month.
My 14 year old cat who died earlier this year cost us a small fortune in vet fees in the last few months of his life.
He developed random breathing problems which meant he had to go into an oxygen cage three times. One time was OOH with a £200 charge. He had various tests but they never found a cause for it.
He then started having seizures, it was suggested he have a £3000 scan at the vet hospital which he never had as even with insurance, I couldn't afford.
He then had urinary problems, and he was back and forwards to the vet before they scanned him and found a mass on his bladder, which is what he died from.
His meds were around £100 a month, luckily all vets visits were covered by the vet plan, he had x rays and scans, loads of urine tests (the urine tests were also covered by the plan).
His insurance was £45 a month, but is he had lived the premium would have went up to £100 a month.
I easily spent over £2500 in the last few months of his life and probably got about half of that back from insurance
It's the vet costs that are the killer. I suggest you get good insurance and a credit cad to cover any emergencies.