Covered litter tray(s). Clumping litter (cat’s best really is the best!).
Tall scratching post (google something like cat scratching barrels - they’re tall and sturdy, with hidey holes in the barrel and a bed on the top - definitely the best thing I’ve purchased in my 10 years of cat slavedom).
Good insurance, and I’d go for a “lifetime” plan - means if they develop a long-term condition then you’re not limited to how much you can claim. Pet Plan have been brilliant for me, never had a problem claiming and quick with refunds.
Don’t waste money on loads of toys. Maybe a couple of wand-type toys so you can interact with them, but equally straws, scrunched up paper, ping pong balls and cardboard boxes are just as exciting for them.
A good carpet cleaner - I get one by Dr Beckman from Amazon. Really handy for when they vomit up a hair ball on the carpet, cleans up any stains a treat.
A good cat carrier. Ideally with top and front loading doors, gives you more options depending on how wriggly your cat is to get in and out on vet visits!
Most importantly - spayed/neutered and microchipped (and update the chipping company if you move house).
Actually - the most important thing is to prepare yourself for how much they are going to totally steal your heart. I’d always been a dog person and thought of cats as being a bit “meh”. Totally blindsided by my love for them.
And, there is only one rule on here - PHOTOS PLEASE 😂💕😂