Any personal experience is long out of date and food/litter depends a lot on the cat. Some are fussy, some aren't. Ours wasn't - she would eat anything from day 1 and didn't care what sort of litter was provided. The place you're getting the cat from will tell you what the cat is used to for food & litter. Start with that, and make gradual changes if you want. For a tower, I'd start at Petbarn or similar or Kmart for the basics. Even Temple & Webster stock towers. Some go from floor to ceiling and look quite stable and don't take up much floor space.
You might want to wait a bit to see what your catto's personality is like - they might enjoy a view out the window later on as they get used to their new home. To start with, they'll probably be pretty cautious as they get accustomed, and will be looking for security over stimulation. Once they get confident, they'll use the tower more and more I reckon. So this might not be an immediate purchase but a later one. Even a stack of sturdy cardboard boxes taped together would do to begin with. Jackson Galaxy has excellent videos on youtube about how to introduce a cat to a new home - worth looking up.