I would probably recommend waiting until a couple weeks before you plan on purchasing. A month in computer parts times is a long time, and prices and products will change in that time.
Does your budget include a monitor, and an OS? If so, you are looking at about $500 for the tower, with $200 invested into a monitor and windows 7 (fyi).
well I don't really plan on purchasing until black Friday or cyber Monday anyways.
Also, my budget does include the OS and monitor. Unfortunatly money is a little tight right now