Okey cokey. Taking your 'essentials' literally (and looking at your other thread as well):
Plastic Litter tray. (Probably 2 - a spare is handy.)
Litter. (My cats' personal favourite has always been Fuller's Earth which is available from any supermarket. One bag at a time probably until your kitty has used it and given the seal of approval.)
Litter scoop.
Good kitten food. (Don't use adult food because it's not formulated for a kitten.)
Brush and cat nail clippers. (The earlier you can get the kitten used to grooming and nail clipping the better. The nail clippers should be cat-designed but the brush can just be something from any shop or the internet. I've found the cats like best a comb-type brush. Stiffish bristles in a row of three - I think they're actually called 'styling brushes' or something - but experiment. You may have a good one around the house.)
Everything else should probably be around the house, I think. Small shallow bowls for food and water, blanket/rug for sleeping on, newspapers for poo parcels, soft toys which have been discarded by DCs, a big cardboard box and some eg toilet roll innards for playing daft games. (You can buy expensive cat toys but they're often just as happy with rolled scrunched bits of paper or rolled up newspaper; and some of the bought cat toys have nasty hard or sharp bits inside or button eyes!)
If you've got rid of all the old soft toys, buy some from the local charity shop - some little ones are good - and put them through the washing machine on a soft wash. They may not say they're machine washable but they pretty well always are which is just as well when the little blighters decide to 'dip' them in their food.
I've probably forgotten something - others will doubtless add.
