Help with basic horse prices?

i live in illinois and i recently decided to get back into the horses. i am looking at a horse right now but before i buy it i want to set up a "budget" i would like to know how much food, care, equipment, etc. is. if someone from illinois could maybe help me out and give me a list of things i need and about how much a month or year it is i would greatly appreciate it. also if you have a gelding for sale around $400 let me know.