Latest / Matmonim: Daf Yomi by Rabbi David Lapin
Bava Metzia 56-57a Ethics and Commerce - אונאה וביטול מקח
The right to cancel a sale can stem either from one party having mislead the other, or from having transgressed the prohibition of אונאה
Source Sheet
The skinny
The skinny isn't ready yet — notes appear once the transcript is processed.