A Collar
We suggest an 8" collar that has an elastic section so your kitty won't get strangled if her collar gets caught on something.  The elastic allows the collar to expand enough to allow your kitty to pull her head out.  DO NOT get a rigid flea collar.  We have rescued strays people had put flea collars on when they were kittens, then the cats grew and grew and no one ever adjusted the size of the collar.  One cat's collar  in particular was so tight that we were amazed he hadn't asphyxiated.  The collar was so tight, it left an indentation in his neck and fur that lasted for months after we rescued him!  PLEASE don't use rigid collars on pets.  Although we never adopt to homes where a kitty will be allowed to go outside, some organizations do.  Even inside cats can dash out a door when you're looking away, when guests come over, when kids don't shut a door all the way, etc., so ALL cats—even those who never go outside—should have a collar unless they're microchipped (see below).

A Tag
It's the law that your kitty has to have permanent identification, which the law defines as an implanted microchip or an engraved tag.  Due to the possibility of a collar and tag coming off the pet, being removed and thrown away by someone who might find a pet and not want to return it to its owner, etc., we strongly urge that you have a microchip implanted in your kitty.  The procedure takes just seconds, is affordable and is the only sure, long-term method for a pet's owner to be found.  If for some reason you decide not to have your kitty microchipped and opt instead for a tag and collar, the tag should have engraved on it the pet's current address and TWO phone numbers (including area code).  One of the phone numbers should be yours; the other should be a "permanent" number for a friend, family member or veterinarian who's not likely to move.  It is not necessary to put the pet's name on the tag.

A Secure Pet Carrier
Due to cats' skittish natures, cardboard boxes and holding your cat in your arms for transport are NOT recommended.  We suggest you purchase a metal and plastic pet carrier large enough to hold your kitty when she's full grown—not just when she's a kitten!  We prefer the type that has a door on the front as well as on the top.  They're more expensive, but are much more convenient.  Not only that, you're much less likely to be nipped at when removing your kitty through the top of the pet carrier than when you reach into the carrier from the front.  (We know this from many personal experiences.)

Premium-Quality Cat Food Appropriate For Your Kitty's Age And Type
Grocery-bought, "Sunday paper coupon" cat food has historically not had the nutritional value that veterinary clinic-bought or pet store-bought food has.  Luckily for all of us, now at least one of the brands that was for years only available at pet stores and veterinary clinics is available at many supermarkets and discount clubs.  Better-quality food is not only inherently healthier for cats, thus meaning less trips to the vet, it is more completely metabolized by cats, so they get better nutrition and leave less waste in the litter box.  Additionally, due to the food's nutritional profile and higher degree of metabolism, the waste that's left behind in the litter box is less odorous.  If you feed your cat cheap food, you're not providing the nutrition your pet deserves and you're likely going to subject your cat to potentially serious (and expensive) health issues in the future.

A Litter Box
The time to buy a litter box is before you get your kitty home.  You'd be surprised at how many people are so tied up in the emotional part of bringing a new cat home that they forget to get the kitty a litter box.  :-)  There are many options when it comes to litter boxes (covered, uncovered, automatic, etc.).  If the kitty has been in another home and has been using a certain style of litter box, it's best to get the same style for your place.  We don't recommend automated litter boxes because many cats are frightened of them.  Some cats are wary of using covered boxes, while others prefer them.  Luckily, litter boxes aren't expensive, so even if you buy one your kitty ends up not liking, you won't have wasted a bunch of money.  We suggest that you donate the unused box to one of your local rescue groups, shelters or humane societies.

Cat Litter
Again, there are many options and we'll be glad to offer our advice, but in general we recommend natural (unscented, non-chemically-treated), clumping litter like our DooDoo Voodoo All-Natural Clumping Litter (this links to a PDF file about our litter; the file is 332KB in size).  This type, which allows you to scoop out the liquid and solid waste, but not throw out all the litter every few days, is better for the environment, preferred by cats and less expensive in the long run.  Don't forget to get a litter scoop.  Metal litter scoops work best for use with clumping litter.  No matter how heavy-duty they seem, we've never found a plastic scoop that (a) worked well with clumping litter or (b) didn't break.

Zip-Lock^® Bags
For scooping clumping litter and disposing of the waste in the least odorous and messy manner possible, we recommend the use of Zip-Lock-style reclosable bags.  If you live near a Sam's Club store, we suggest you purchase the multi-packs of the 1-gallon size, especially if you have more than one cat.  Another option is to use plastic grocery bags, but because these aren't reclosable, they need to be sealed with twistees, which are lethal to cats if swallowed.  So, if you're going to use plastic grocery bags with twistees, PLEASE be careful to keep the twistees away from your pets!

Food & Water Dishes Or Bowls
These need to be made of glass, ceramic or metal, but not plastic.  Why?  Because the chemicals in the plastic leach into the food and water, causing many pets to get ulcers on their mouths due to allergic reactions.  Plastic is also not as completely cleanable or fully sanitizable.

A Cat Brush & A Cat Comb
Cats seem to prefer these at different times, so we recommend you get a flea comb with very tightly-spaced teeth (this also helps remove loose fur, even on cats who never get fleas) AND a cat brush.  Brushing and combing your new pet will really help her bond to you, so do it often.

A List Of Contact & Emergency Phone Numbers
The time to get together any phone numbers you might need in an emergency is BEFORE you need them in an emergency!  Make a list of all the 24-hour emergency clinics, vet clinics you frequent, your veterinarians' home & cell numbers if you have 'em, secondary caretakers in case something were to happen to you, pet sitters, poison control centers, animal cruelty hotlines, etc. and be sure to carry the list with you in your car, purse, etc., as well as posting the list at your home in a convenient, not-easily-forgotten place.

A Carton Of Cat Treats
There's nothing like shaking a little milk carton-style box of cat treats to make your cat come running when you need her to come to you.  Many of the cats we've rescued have preferred the crunchy-style treats we've brought home.  (These are better for their teeth, too.)

A Few Cat Toys
Cats need safe things to play with, otherwise they tend to get into mischief that you don't want 'em to and that can be dangerous to them.  We like toys that can be thrown in the washing machine, as well as bizzy balls and sponge balls.

Flea & Heartworm Preventative
It may seem to you that this should appear on another list instead of this one, but we can't stress strongly enough how important it is to regularly treat your kitty with these preventatives.  Until you've had a flea infestation in your pet and your home, or until you've seen what heartworm can do to a cat (most often kill them in a most unpleasant way), you may not understand and place enough emphasis on these preventatives.  Flea and heartworm preventatives can save you tons of money, tons of aggravation and, most likely, the life of your pet.  We recommend Revolution for cats.

A Camera, Preferably A Digital One
Your kitty is going to do all sorts of cute and wonderful things that you'll want to share with I-CAN or whatever other organization you adopt from, plus all your friends and family members, so be sure you have a camera handy for those special moments that only happen once.  A digital camera is great because there's no film to buy or pay to have developed, plus you can e-mail the pictures instantly to as many people as you want...all without any additional cost.

A Pet Hair "Tape Roller"
No matter how much of a pet lover you fancy yourself, if you're expecting company or leaving for a business meeting and you find yourself or your furnishings covered with fur, there's nothing like a "tape roller" to make quick work of removing the undesired fur.  Also, if your pet sleeps with you, you might find it useful to "roll" your comforter each morning to remove the pile of fur that always seems to remain where kitty or doggie slept!  (We do this and it takes just seconds to give your comforter a quick cleaning.)  These tape rollers are available at most pet supply stores, discount stores & some veterinarians' offices and are well worth the few bucks they cost!

You might also want to pick up a Pet Hair Magnet™, which is a rubber-bladed squeegee-type device that is phenomenal at removing even woven-in pet hair from carpet, upholstery, bedding and more.  Type "Pet Hair Magnet" in your favorite search engine and pick one up.  You'll be glad you did.