Oh and basic medical kit!
So you are gonna need loads of things but starter things are gonna be a halter (rope or nylon. Rope is gonna be better for training), lead rope, hoof pick (most crucial grooming tool), hard brush, curry comb. (Those are your most important grooming tools but there are many other grooming supplies.) You want to wait to get a saddle so you make sure it fits the horse, saddle pad, bridle, bit or hackamore, reins, lunge line, whip, shampoo, conditioner, sponges, leather cleaner. You can buy boots or Polo wraps too. Those are all the things I can think of off the top of my head.
Don't waste money on a saddle until you already have the horse. I see new horse owners buy ill-fitting saddles and regret it with their chiropractic care bill.
Need: shelter, hay, grain, water, halter and lead rope, hoof pick, stiff brush, curry comb, saddle, saddle pad, bridle and reins.
Want: polo wraps, splint boots, or SMB boots, more brushes and bathing supplies, lunge line, lunge whip
To start you will need a safe area (with access to shelter, food and water) and a halter and lead.
In the future you will need lots of stuff! But you can add stuff to your collection there becomes a need for it. No reason to pay for a bunch of stuff that you may or may not use.☺
Halter and lead, grooming supplies, basic first aid supplies, blanket (if need be), depending on disipline of horse you will need tack. I know Wintec sells a English tack set for about $500. I'm sure you can find western tack for cheap too!
Needs: Halter and lead, grooming things (2 main brushes, curry and hoof pick) tack (if it's a riding horse) most basic tack only, saddle, saddle pad, bridle, reins.
Wants: Treats, blankets, extra saddle pads, things like that.
I got a halter lead and grooming kit for my horse, it wasn't until a few weeks later I started looking at tack.
I may have misunderstood your question. If it's like what you'll need for a horse then; brushes, tack, blankets, halter.