Kitty Litter Tray
Kitty Litter
Wet Cat Food
Dry Cat Food
Kitty Litter Scoop
Cat Toys
Cat scratching post
Cat bed
Food Bowls
Water Bowls
Flea Brush (Just incase, not too expensive)
Cat Brush
From the vet you'll need flea treatments (Advantage, Frontline or Revolution) and a Worming treatment as well - Don't buy over the counter medicines
Hmmm...Thats all I can think of for now!
But don't forget you'll also need to budget for vaccinations (at 6 weeks, 10 weeks and 16 weeks) and desexing (at around 6 months) and microchipping (if not already done when you get your kitty)