Well here is a pretty generic answer; you will need a reloading press, dies, a powder scale, plus components (bullets, brass, primers, powder), and quite a few assorted items that are helpful, like case trimmer, tumbler, bullet puller, ect.
A good resource for starting is a good reloading book. I prefer "The ABC's of Reloading".
Get a good reloading manual to start. The 49th edition of the Lyman Reloading Manual is pretty popular and can be found for less than $20. It'll give you a good overview of what all is involved and you can then develop your "shopping list" from that.
Just like any hobby, it can be as expensive as you can afford or as inexpensive as you can handle.