GSnap by GVST is the famous freeware pitch corrector used by countless bedroom producers. It offers key/scale detection, attack/release controls, and subtle or robotic effects. Download the VST version + a legacy VST-DX wrapper.
Antares Auto-Tune is proprietary commercial software. A single license costs between $99 and $499 depending on the version (Auto-Tune Access, Pro, or Artist). , nor do they offer it as freeware for Audition 1.5. antares autotune for adobe audition 1.5 free download
If you are using Adobe Audition 1.5 and need pitch correction without the price tag or security risks, consider these alternatives: GSnap by GVST is the famous freeware pitch