BT BM 47a(53) :כמאן כתבינן, וקנינא מיניה במנא דכשר למקניא ביה‏ : according to whom do we write: "I bought it from him with a vessel with which it is proper to acquire" [but understood in the text as an actual vessel?]
See the entire entry for mān, mānā n.m. vessel; garment