Here's a few budget options:
Antares Auto-Tune EFX ($99):
http://www.guitarcenter.com/Antares-...93-i1428200.gc
Antares Auto-Tune EFX Vocal Suite ($149):
http://www.guitarcenter.com/Antares-...75-i1480418.gc
You'll get the same basic functionality out of Auto-Tune, though you won't have the in-depth pitch editing that you can do with the EVO version. It's quick, cheap, and super easy to use.