It really depends on what and how much you plan to brew and how sophisticated you want to get.. There are complete home brewing kits you can buy ranging from around $100 and up.
I'm not a home brewer, I'm technically not even a brewer, I just started helping and learning brewing at the brewery I bartend and manage.
It's brand new in 2012 so it's a state of the art system and everything is computerized, my brewing knowledge goes as far as which button to push and when lol.