Wet food is best.Mine do very well on Friskies and Fancy Feast pate, they have been on this diet since they were kittens. As others have said purchase what your budget allows .
I used to groom dogs and you did the right thing by getting her shaved so her skin can breathe and heal, some dogs are difficult to groom too when matted and act odd for a few days
I love Costco and shop there regularly. I get my cat litter (42 pound box) for around $12.00(,clumping litter ). I buy a lot of clothes, peanut butter, coffee, had a eye exam and ordered my glasses from the optical department also had my Covid booster at the pharmacy, they have a very good...
So sorry for your loss, we too lost a cat a few years ago to what the emergency vet suspected was a bad heart, our cat Jack literally dropped dead next to us in the kitchen he was fine one minute gone the next. Please don't blame yourself.
I always say feed what you can afford and your cat will eat without causing you to tear your hair out with frustration. Mine eat Friskies and Fancy Feast pate mixed with kibble,they are doing very well ,but as others have said what works for my cats might not work for you.